# WHy 9 bar are standard ? why not less ?



## Olek (Aug 21, 2019)

Hello

I am seeing that I can extract coffes with 5bar, or ranging slowly (ramp) from 2 to 8 bar, and in both case the coffee are good.

I wonder, (sorry for the stupid question) why 9 bar 23 28 sec, is considered a standard.

If a coffe is done with 4 bar on a Rossi group (may be that makes a difference) it flows slowly and it is tasty.

WIth the sort of "pre infusion" (or low pressure start) I use, seem to me that the puck is easily disturbed with 9bar pressure, it il always moist almost muddy ,at the end.

(may be it is only due to the regulation that send pulses of pressure (not smooth enough, I ordered the strong resistance to help the dimmer as suggested)


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## Rob1 (Apr 9, 2015)

I think it's just a standard from tradition. A lower pressure will still give you espresso but might lack the mouth feel you'd typically associate with a higher pressure extraction. Getting good coffee from anywhere between 4-9 bar extractions is expected really. Flow rate is determined by grind and pressure so you need to grind finer at a higher pressure to achieve the same flow rate as you get from a low pressure shot, grinding finer is generally considered desirable as it pushes extraction up.

If you are seeing the puck being disturbed with a low-to-high pressure ramp it could be bad preparation or a bad grind, or maybe not fresh coffee. The puck shouldn't break apart and show a massive increase in flow until the end of the extraction (you should be turning the pump off just as it starts to happen


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## ashcroc (Oct 28, 2016)

Rob1 said:


> I think it's just a standard from tradition. A lower pressure will still give you espresso but might lack the mouth feel you'd typically associate with a higher pressure extraction. Getting good coffee from anywhere between 4-9 bar extractions is expected really. Flow rate is determined by grind and pressure so you need to grind finer at a higher pressure to achieve the same flow rate as you get from a low pressure shot, grinding finer is generally considered desirable as it pushes extraction up.
> If you are seeing the puck being disturbed with a low-to-high pressure ramp it could be bad preparation or a bad grind, or maybe not fresh coffee. The puck shouldn't break apart and show a massive increase in flow until the end of the extraction (you should be turning the pump off just as it starts to happen


That's strange. I found I had to grind a bit finer when I adjusted my OPV down 9 bar from 11.


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## Nicknak (Aug 10, 2018)

ashcroc said:


> Rob1 said:
> 
> 
> > I think it's just a standard from tradition. A lower pressure will still give you espresso but might lack the mouth feel you'd typically associate with a higher pressure extraction. Getting good coffee from anywhere between 4-9 bar extractions is expected really. Flow rate is determined by grind and pressure so you need to grind finer at a higher pressure to achieve the same flow rate as you get from a low pressure shot, grinding finer is generally considered desirable as it pushes extraction up.
> ...


 There was quite a bit on here awhile back where people were going down to 6 bar grinding finer and tamping lighter to get better shots ,


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## Rhys (Dec 21, 2014)

Nicknak said:


> There was quite a bit on here awhile back where people were going down to 6 bar grinding finer and tamping lighter to get better shots ,


 I think I brought that up after reading about it. I've got my machine set at 6 bar and quite like the results. Although I'm going off lighter roasts now and may put it back up to 9, or even 8 (which the Conti was set to at the last Rave day)


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## Olek (Aug 21, 2019)

Thanks for the answers . So you see a difference in pressure (and grind) depending of the roast ? and darker roast would be better with stronger pressure, is it what I read ?

The beans I use are not "fresh" indeed, moderate crema, it is an industrial "Hema" dark roast, very cheap (8€ Kg), but usually the pucks are perfect (with typical 9 bar all along)

I really suspect the pump regulation not smooth, pulsing, being erratic at some moments (this is an Ulka UP5, I was told to add a resistance to smoothen the regulation)

I wil try finer grinds ( I forget to say only with the1 cup basket that the pucks are muddy, contains 7 to 9 g officially, but more than 10 if I fulfill).

I use that tool that turns, to distribute well (plus a tap first, a rought finger distribution, and I turn the tool counterclockwise before turning normally, then tamping, usually it works like a charm with 8.5g-9g in that basket).

Regards


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## Olek (Aug 21, 2019)

The finesse of the grind have 2 "sides of the coin", as a too much packed puck is more prone to channeling.

I hade a better puck by using a thinner grit in the end


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## Hasi (Dec 27, 2017)

then again, slow ramp and lower pressure reduce chances of channelling.
With a lever or pressure profiling machine you can, at times, even watch chanelling being 'healed' through declining pressure towards end of a shot (not that I would ever get channelling )


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## Olek (Aug 21, 2019)

Ah , I had some succes with blonding by stopping the extraction a second, then do again (wich makes a ramp again)

I hope to have a better managment of pressure soon. At the moment, I am inclined to use the "full basket method" each time (full not overloaded, but not really weighting) , and the thinnest grain possible.

In the end we try to copy the lever machines , I suppose .Here is mine


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## ajohn (Sep 23, 2017)

The numbers come from 25ml, 25sec single and I believe 8 bar but may have been 7 1/2. The other numbers probably from the USA (fl ozs) 30ml, 30sec. As far as we are concerned 1ml is the same as 1g.

So you have 1ml / sec in both cases and an associated quantity of grinds, a single in this case. 9bar came about from vibratory pumps performance compared with rotary. So this is the pressure some one decided produced coffee according to their specification. This is also tied into how grinders are specified. An Italian spec that I have seen mentioned but never found. The makers might for instance state the time to grind a single. The grinder being set to give the times and flow rates as above.

It's interesting to think what happens if infusion is used and grinder set to give the same numbers and ratio out.

Personally I have found that it starts getting a little difficult to make beans taste as they should do if things deviate too much from these numbers. These figures also imply that a 25/7 ratio is used (or 30/7  but is the USA ever right about anything?) It's a fact that ratios of this level may suite some beans and some drinkers.

Some one pushed me to trying 40sec shots some time ago. Not keen. Some one else messing with long infusion times and found fruit notes that shouldn't be there. Taste anyway is subjective and up to the drinker.

John

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## MWJB (Feb 28, 2012)

ajohn said:


> The numbers come from 25ml, 25sec single and I believe 8 bar but may have been 7 1/2. The other numbers probably from the USA (fl ozs) 30ml, 30sec. As far as we are concerned 1ml is the same as 1g.
> 
> So you have 1ml / sec in both cases and an associated quantity of grinds, a single in this case. 9bar came about from vibratory pumps performance compared with rotary. So this is the pressure some one decided produced coffee according to their specification. This is also tied into how grinders are specified. An Italian spec that I have seen mentioned but never found. The makers might for instance state the time to grind a single. The grinder being set to give the times and flow rates as above.
> 
> ...


 Traditional espresso ratios & times are so broad (Illy broadest, INEI tightest, SCAA somewhere in between) that all the published definitions overlap.

1ml/1g per second is not a thing, it doesn't guarantee you anything. Think about it, if you make a double in a similar time frame, or a longer shot, your flow rate increases dramatically. Extraction can be normalised so that it's the same for 2g/sec as it is for 1g/sec. Flow rate is just a byproduct of grind setting, grind setting targets extraction.

1ml would be the same as 1g if there was no crema and if glasses/receptacles were calibrated & 1ml resolution & and they are typically neither.

As to what bar works? Any that actually is enough to push the water through the puck and make a normally extracted drink. Most people have no idea what their pressure actually is but it doesn't stop them making tasty drinks. Pressure will float with grind adjustments and bean used.


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## Mrboots2u (May 10, 2013)

What are fruit notes that shouldn't be there? Coffee is a fruit..... It tasted of banana but should have been apricot.

Most fruit notes are more generally a combination of acidity and sweetness to evoke fruits in the taster.....

1ml in one sec is no more magic than a 1:2 in x seconds. It's one of those things that seems to be held onto as a significant measure where I am not sure what the actual reasoning is. See @MWJB posts above.


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## Olek (Aug 21, 2019)

My take on the results with less pressure or a ramp (not up to 9, more 8bar) is the drink is more smooth, more aromas, I regret my taste is not trained enough to recognize the types of flavor, but the coffe is good even with long ratios, and more sugar/type with 1:2 ratio, despite a very ordinary dark roast. (ordinary but decent)

the pump is too shaky when I raise the power, so I experiment small channeling more often than wanted (I think the pump is the cause).

but late enough in the .shot.


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## Olek (Aug 21, 2019)

MWJB said:


> Traditional espresso ratios & times are so broad (Illy broadest, INEI tightest, SCAA somewhere in between) that all the published definitions overlap.
> 
> 1ml/1g per second is not a thing, it doesn't guarantee you anything. Think about it, if you make a double in a similar time frame, or a longer shot, your flow rate increases dramatically. Extraction can be normalised so that it's the same for 2g/sec as it is for 1g/sec. Flow rate is just a byproduct of grind setting, grind setting targets extraction.
> 
> ...


 Without the dimmer, I had consistantly 9bar or 9.5 , depending only of the OPV regulation (whatever the grain and basket) I did see that on a mano.

Now I noticed that even if the pump send 3-4 bar, the pressure add and raise until the OPV opens. (may be just the regulation do not work fine enough yet, but it is may be normal because of the design of the pump : without much resistance it send 4 bar but the double valve retain the pressure on one side and the dimmer only slow the vibes, As long the current make the pump move, the pressure will rise, more or less fast that is the main difference, the "ramp")


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## jj-x-ray (Dec 31, 2017)

I may give 6 bar a try the next time I have my classic open...I'm on 9 at the mo

Sent from my SM-G960F using Tapatalk


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## Inspector (Feb 23, 2017)

I will try 6bar on my classic too this evening. Always wanted to but lazy to open it up and adjust


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## ajohn (Sep 23, 2017)

MWJB said:


> Traditional espresso ratios & times are so broad (Illy broadest, INEI tightest, SCAA somewhere in between) that all the published definitions overlap.
> 
> 1ml/1g per second is not a thing, it doesn't guarantee you anything. Think about it, if you make a double in a similar time frame, or a longer shot, your flow rate increases dramatically. Extraction can be normalised so that it's the same for 2g/sec as it is for 1g/sec. Flow rate is just a byproduct of grind setting, grind setting targets extraction.
> 
> ...


 The 1g / 1ml per sec was mentioned because it does relate to 2 metrics for "good" coffee that are sometimes mentioned.

The difference in typical rotary against vibrators pumps is correct but makers may set all sorts. A typical might be 8 bar rotary and due to staring differences / different pulses 9 bar vibratory. That's the reason usually given and has cropped up on here before and that reason mentioned. Fact? pass but the 2 are usually set differently. In one instance I believe a certain vibratory pump model is set low. Classic ???

And by the way what I said was that 1g is equivalent to 1ml as far as most people on here are concerned. They may well see ml mentioned some where else and then use gram scales and weigh on that basis instead. Crema is irrelevant.

Just talking brew pressure some do change this on sage dual boilers by setting the machine up so that it's always running in infusion mode. The pump power can also be changed during infusion. I've found that varying ratios is a better option if some one wants the taste the bean should have. If they don't anything goes. It does with me at times.  Saves throwing beans away.

If I remember correctly @joey24dirt did dimmer mods on a DTP and mentioned surprising fruit notes and etc. Reading between the lines I don't think he was that impressed. He has drunk a lot of coffee. I think he used the usual chinese triac speed controller board. I'd assume it would only work when the power getting to the pump was very restricted. It moght also be possible to adapt a chinese relay type timer board to set the infusion time. The triac on the power controller wont be bothered if it' shorted out via a relay.

My DB now runs with 6secs of infusion. The pump goes full power just as the entire base of the basket is wetted out. Seems better to me.

John

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## Mrboots2u (May 10, 2013)

But what's makes 1ml in 1 second good...



ajohn said:


> The 1g / 1ml per sec was mentioned because it does relate to 2 metrics for "good" coffee that are sometimes mentioned.
> 
> The difference in typical rotary against vibrators pumps is correct but makers may set all sorts. A typical might be 8 bar rotary and due to staring differences / different pulses 9 bar vibratory. That's the reason usually given and has cropped up on here before and that reason mentioned. Fact? pass but the 2 are usually set differently. In one instance I believe a certain vibratory pump model is set low. Classic ???
> 
> ...


 Who and why said its a metric of being a good coffee


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## MWJB (Feb 28, 2012)

ajohn said:


> And by the way what I said was that 1g is equivalent to 1ml as far as most people on here are concerned. They may well see ml mentioned some where else and then use gram scales and weigh on that basis instead. Crema is irrelevant.
> 
> John
> 
> -


 Crema is not irrelevant, because the traditional method of using ml includes the crema, which has much less mass than water at 20C, let alone hot coffee with a high proportion on non-dissolved solids. Yes, you can have a shot that is very close to ml in g, but next bean you might get a big disparity between the 2 (still the problem of a lack of ml graduations).


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## Olek (Aug 21, 2019)

let's say it makes 25 g in 25 sec, for 12,5g then ? It is not enough grind for 2 cups, and a bit too much for one , may be.

I likes small coffe as 20 25g with 15g in the basket, (with a lot of crema) I see ratios more than gr/sec used I did not understand at first but 1:2 to 1:2.5 seem to have much taste.

Now I also like to obtain 30 to 40g that do not taste watery, and it seem to be easier with lower pressure and slow start


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## Inspector (Feb 23, 2017)

Ok,

I have adjusted my classic to static 7 bar (previously was static 9bar). Shots were pouring good already previously but now seems even better. Mouthfeel definitely less than before but shots are sweeter and much smoother. I am not too sure why but i had to grind finer to get the same extraction time. i will experiment more.


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## Olek (Aug 21, 2019)

Inspector said:


> Ok,
> 
> I have adjusted my classic to static 7 bar (previously was static 9bar). Shots were pouring good already previously but now seems even better. Mouthfeel definitely less than before but shots are sweeter and much smoother. I am not too sure why but i had to grind finer to get the same extraction time. i will experiment more.


 May be just a question of personal taste.

Same to me a very thin grit to obtain 20g for 10g coffee. Time 26 sec. Plus moistening.

Smoother, less explosive taste but enough aromas. I will test with the Passacquala soon. It have much taste originally.


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## Mrboots2u (May 10, 2013)

Olek said:


> let's say it makes 25 g in 25 sec, for 12,5g then ? It is not enough grind for 2 cups, and a bit too much for one , may be.
> 
> I likes small coffe as 20 25g with 15g in the basket, (with a lot of crema) I see ratios more than gr/sec used I did not understand at first but 1:2 to 1:2.5 seem to have much taste.
> 
> Now I also like to obtain 30 to 40g that do not taste watery, and it seem to be easier with lower pressure and slow start


 too much taste or volume ? the bigger the ratio the weaker the strength of the coffee. Of course it may increase extraction this may be a good thing for a lighter roast coffee au be not so great for a darker roast.

Ig you dint want watery ( stronger ? ) then change your brew ratio to get the strength you want.


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## Olek (Aug 21, 2019)

SOrry it may be due to my simplified English, I mean that 20 25 g are generally well tasty and strong. WIth Italian type expresso this is really good.

The extration level change with lower pressure and moistening before extracting.

I find an interesting video showing that, with classical parameters, after 28 sec, the sourness ("bad" sourness" raise

The extraction time is divided in 3 sequences of a few secondes each

Ten first seconds, oils are extracted , this is the base, the structure.

10 to 20 sec, acidity, floral tastes

20 28 sec, is the sugar taste, smoothness

AFter 28 seconds, "negative sourness " and astringency.

Keeping that in mind while my extraction lenghten because of the initial moistening, it is no surprise some extraction may have a sour taste.


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## Mrboots2u (May 10, 2013)

In that clip looks like she is splitting the shot and then tasting it, but a shot is the sum of it whole parts , and those parts are only a refection of how the shot is set to brew .

No magic happens at 28 seconds in every shot, the time taken to come out will be a function of dose and grind creating resistance. I could be pulling a shot at 20 seconds that is balanced and sweet and one at 40 seconds that is balanced and sweet and I have had plenty untasted shots at 30 seconds.

What foes the first ten seconds taste like good bad ? if bad do we get rid of that too?


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## MWJB (Feb 28, 2012)

This splitting of the shot serves no purpose, your shot is all that you extract as a whole. None of the individual portions taste right on their own. You just need to be aware of brew ratio & grind setting. The coarser you grind & longer you pull the larger these 3 portions become but still have the same relationship.

It would be more useful to pull 3 separate shots, one shorter than usual, one usual, one longer than usual to see how that affects flavour balance.

The acids in coffee extract fairly uniformly and in proportion relative to total extraction, what drives flavour balance is the difference between not enough, preferred amount, too much. Not all the acids in coffee taste acidic.

https://scanews.coffee/podcast/52/tracking-and-tweaking-your-extraction-dr-marco-wellinger-expo-lectures-2018/


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## ajohn (Sep 23, 2017)

Olek said:


> let's say it makes 25 g in 25 sec, for 12,5g then ? It is not enough grind for 2 cups, and a bit too much for one , may be.
> 
> I likes small coffe as 20 25g with 15g in the basket, (with a lot of crema) I see ratios more than gr/sec used I did not understand at first but 1:2 to 1:2.5 seem to have much taste.
> 
> Now I also like to obtain 30 to 40g that do not taste watery, and it seem to be easier with lower pressure and slow start


 There are 2 well known terms covering this area, risteretto and lungo -  some view the latter one in a different way but neglecting that one restricts the size of the shot the other increases it. Grams of grinds don't change. Grind needn't and shouldn't really, just shot time/volume out. While a ratio of 1 to 2 tends to be mentioned a lot there is nothing sacred about it. In fact I would be inclined to say it's bad news for any fresh roasted bean i have tried. It's normally higher than that. 2.6 has been mentioned but what people drink may well influence it. I drink americano style, some milk based others straight espresso. The latter is a tough area as coffee isn't naturally sweet but ratio, grind and quantity are still the control along with choice of beans.

Then grind can be changed.

It's all too complicated really as there are too many variables. Personally I stick to a 30sec shot time and accept a certain amount of output change. I wouldn't if the taste changed. In my view that can change by more than 10% without any problems taste wise. Ratio with the bean I used most is 3 based on 13.5g grams of what is basically a strong bean. As I need some beans to warm up from the fridge I just pulled and drunk one that had a ratio of 4+. I was surprise how little edge it added to my 300ml americano. Normally with this bean I go risteretto for my wife and cut the time to 20sec. It dilutes some aspects of the taste. Other beans vary. One for instance is best in a drink of the same size using around 8 grams. Any more and it's too strong to be able to taste the various notes it has, just one dominates. A commercial arabica bean from Lavazza I have tried out of curiosity is most definitely at it's best as directed on the package 14 in 60 out. I used 17 but do like strong coffee. Another same source no directions was best at the usual circa 2.6 ratio.

I'm well used to detecting the taste of water in coffee from using a Barista Express and using the single with it for my usual 300ml drinks. It holds circa 10g, little bit less of some beans. Only strong beans would cut it without traces of water in the taste but were still too weak for me. That's brewing at 15bar as well. This also taught me that even fill height in the basket matters.  It's amazing the lengths I went to because of this limitation. People might think lower fills and finer grinds have to be better - I'd just say really !!! It often isn't the case.

The main control of strength of taste is quantity and beans. There is no way any normal person would try my shots as an espresso - IMHO anyway, It's thick and sticky which saw the end of playing with shot glasses - to much was left on when tipped out. I tried licking a teaspoon once with some on. I could still taste it an hour later. I suspect you may need to revisit the basics and that's based on any bean I have used.

John

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## Olek (Aug 21, 2019)

Mrboots2u said:


> In that clip looks like she is splitting the shot and then tasting it, but a shot is the sum of it whole parts , and those parts are only a refection of how the shot is set to brew .
> 
> No magic happens at 28 seconds in every shot, the time taken to come out will be a function of dose and grind creating resistance. I could be pulling a shot at 20 seconds that is balanced and sweet and one at 40 seconds that is balanced and sweet and I have had plenty untasted shots at 30 seconds.
> 
> What foes the first ten seconds taste like good bad ? if bad do we get rid of that too?


 AS I uindeistand it is a simplified explanation that use the "standard" expresso as a base. Those 23-28 seconds where part of it,as originally a 1:3 ratio (that seem to have changed today for 1:2 or 1:2.5.

I also have 45 sec shots, 'not really 20 sec) but always I count those 25 seconds. It can be longer if the gind is too thin, or there is too much. I think the last part of the shot is not helping, I did witness that more than once, the balance between those 3 small parts is not so easy to obtain probably, but lenghtening the shot I try to avoid.

That said I did see some making ratios 1:1 (dynamite expresso  . I use fairly common standards at last in my part of the world. The shot must be like sirup initially, of course bean and freshness quality matters the most. I was not knowing the taste of ristretto before my coffe adventures , and now I appreciate them a lot. I make weaker ones when I pour milk.

Here is the sort of expresso I like :


















But... I think any quantity and any strenght of coffe can be enjoyeable, assuming the beans are good


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## Olek (Aug 21, 2019)

MWJB said:


> This splitting of the shot serves no purpose, your shot is all that you extract as a whole. None of the individual portions taste right on their own. You just need to be aware of brew ratio & grind setting. The coarser you grind & longer you pull the larger these 3 portions become but still have the same relationship.
> 
> It would be more useful to pull 3 separate shots, one shorter than usual, one usual, one longer than usual to see how that affects flavour balance.
> 
> ...


 Thanks for the link, I will read them. The video is from a professional Barrista (winner of 2018 competition I think) . I do not know , I am a simple amator, but her description make sence to me. what comes from the puck differs along the shot.

When I learned, I had to change one parameter at once, if not it is impossible to compare and to repeat the same shot again. I soon did stick with 25 28 secs , even if now I eventually wait for the shot to blond to cut the pump.

I did not try to get thos 3 main parts, but I will , and let you know what I find


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## MWJB (Feb 28, 2012)

Olek said:


> but her description make sence to me. what comes from the puck differs along the shot.


 Yes, we all agree on that early in the shot is 'not enough/under-extracted', balanced is 'enough/normally extracted', so much that the shot is smoky & drying is 'too much/over-extracted'.

But if you are under-extracting and you still split the shot into 3, the 3 parts will still taste different. Then what have you learned?

If you pull a bunch of good tasting shots, with a balanced taste, the last part of these will still taste thin & bitter. Eliminate that part so the last part is still bright, your shots will tend to be under-extracted.


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## Olek (Aug 21, 2019)

I noticed those sugar taste more or less present ,in small 22 g shots. (Small shots anyway,as 2 cups with 16g)

Lengthening the shot seem to hide them. I find it is not so easy to have nice ristretto as they have a strong taste but with a sugar nuance ,no need at all to add sugar of course.


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## MWJB (Feb 28, 2012)

Olek said:


> I noticed those sugar taste more or less present ,in small 22 g shots. (Small shots anyway,as 2 cups with 16g)
> 
> Lengthening the shot seem to hide them. I find it is not so easy to have nice ristretto as they have a strong taste but with a sugar nuance ,no need at all to add sugar of course.


 There is a phase of low extraction that can be sweet but simple flavour (about 12-14%), before you get into the sour/tart region. Get past the sour/tart region (maybe over 17-18%) and you get sweetness coming back again, but with ripe fruit acidity.

There's next to no sucrose in roasted coffee.

I never take sugar in my coffee, I expect it to have it's own sweetness. If you can't get past the sour/tart phase, then maybe the sweeter low extractions might be your best bet (I don't mind the taste, but they're a bit gooey & give me the burps).


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## Olek (Aug 21, 2019)

MWJB said:


> There is a phase of low extraction that can be sweet but simple flavour (about 12-14%), before you get into the sour/tart region. Get past the sour/tart region (maybe over 17-18%) and you get sweetness coming back again, but with ripe fruit acidity.
> 
> There's next to no sucrose in roasted coffee.
> 
> I never take sugar in my coffee, I expect it to have it's own sweetness. If you can't get past the sour/tart phase, then maybe the sweeter low extractions might be your best bet (I don't mind the taste, but they're a bit gooey & give me the burps).





Mrboots2u said:


> In that clip looks like she is splitting the shot and then tasting it, but a shot is the sum of it whole parts , and those parts are only a refection of how the shot is set to brew .
> 
> No magic happens at 28 seconds in every shot, the time taken to come out will be a function of dose and grind creating resistance. I could be pulling a shot at 20 seconds that is balanced and sweet and one at 40 seconds that is balanced and sweet and I have had plenty untasted shots at 30 seconds.
> 
> What foes the first ten seconds taste like good bad ? if bad do we get rid of that too?


 That sounds interesting, I have not equipment to make precise comparaison (doing "Manual pID" with thermometers and vapor button) ,

What was suggested to me is 9bar (soon attained) allow the fine to drip at the bottom of the basket allowing them to be extracted.

See at 9 bar, and with 1 cup 7g-9g basket ascaso, a good prep, I obtained some fines (not much but a little) extraction stopped a little late as I had 22g in cup (1:3):


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## Olek (Aug 21, 2019)

I mimic the shaking as done here :

BTW, in French barrista "schools", touching the grind - or the basket - with its hand, is a definitive no-no , I even think I did read you are elimined of competition if doing so.


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## Olek (Aug 21, 2019)

MWJB said:


> Yes, we all agree on that early in the shot is 'not enough/under-extracted', balanced is 'enough/normally extracted', so much that the shot is smoky & drying is 'too much/over-extracted'.
> 
> But if you are under-extracting and you still split the shot into 3, the 3 parts will still taste different. Then what have you learned?
> 
> If you pull a bunch of good tasting shots, with a balanced taste, the last part of these will still taste thin & bitter. Eliminate that part so the last part is still bright, your shots will tend to be under-extracted.


 I think,again ,it is a simple way to explain shoot length ( in speciality coffee probably) she may have learned that in a "barista school" probably..


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## Olek (Aug 21, 2019)

MWJB said:


> Yes, we all agree on that early in the shot is 'not enough/under-extracted', balanced is 'enough/normally extracted', so much that the shot is smoky & drying is 'too much/over-extracted'.
> 
> But if you are under-extracting and you still split the shot into 3, the 3 parts will still taste different. Then what have you learned?
> 
> If you pull a bunch of good tasting shots, with a balanced taste, the last part of these will still taste thin & bitter. Eliminate that part so the last part is still bright, your shots will tend to be under-extracted.


 I think,again ,it is a simple way to explain shoot length ( in speciality coffee probably) she may have learned that in a "barista school" probably..

I do not think she taste any of those parts that have "bad taste" separately, (while making mixes and tasting can be interesting)

I did the test, using 15.5g in a 14g Ascaso basket . 10 sec, 10 sec, 8 sec. The first 2 cups have a very different taste, I had trouble feeling sweetness in the last cup however. But the water I use is somewhat acid so it cut the sweetness (I used to add some tap water in the Brita filtered one, to have more sweetness, but here I forget, I will do the test again soon)


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## MWJB (Feb 28, 2012)

Olek said:


> I did the test, using 15.5g in a 14g Ascaso basket . 10 sec, 10 sec, 8 sec. The first 2 cups have a very different taste, I had trouble feeling sweetness in the last cup however. But the water I use is somewhat acid so it cut the sweetness (I used to add some tap water in the Brita filtered one, to have more sweetness, but here I forget, I will do the test again soon)


 Why 28 seconds total? Usually you'd pick your known good brew ratio & set the grinder so you got the best taste, as long as time wasn't crazy unusual.

Just changing bean, for a similar extraction, can have a huge effect on shot time. Trying to nail a given shot time & ratio makes things more complicated & difficult.


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## Olek (Aug 21, 2019)

I don't know, out that this is a standard that have been given to me, always, so I try to adjust my grind to obtain the wanted cup quantity in 25 secs, (meaning the blonding comes after that time) It is easily seen in the creama.


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## MWJB (Feb 28, 2012)

Olek said:


> I don't know, out that this is a standard that have been given to me, always, so I try to adjust my grind to obtain the wanted cup quantity in 25 secs, (meaning the blonding comes after that time) It is easily seen in the creama.


 What is your strike rate on coffees made, at the same weight, from the same dose, in 25s?


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## Olek (Aug 21, 2019)

I do not understand "strike rate "

The only ratio I use, because it is simple, is grams in basket vs grams in cup so it can be from 1.5 to 2.5 or 3:1 at times.

The goal is generally a ristretto, to make eventually a latte (milk crema/foam with a ristretto poured in ) or to drink as it is if the beans are good and fresh.

I did test again , with 16g in basket at a final 1.5:1 ratio (24gr, was not the goal but ...) WIth an (april) industrial dark roast, 20% robusta, no much fruit flavor expected but clearly the first 10 sec gives a concentration of something differing a lot of the next 10 secs, while the last 8 sec cup have a flat taste, no acidity at all if not "sugar like".

The 10 last seconds I added are a bit astringent indeed

sorry for the pics quality

I agree this is may be not so useful unless one knows how to extract more "flower fruit flavors/acidities) or more of the first part . I did not see such explanations elsewhere, but I admit did not read so much of expresso scientific analysis.


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## Olek (Aug 21, 2019)

See pics of "shooting our shots"  ommonly appreciated expressos there : http://expresso.1fr1.net/t15120p200-shoote-ton-shot-v-des-photos-de-vos-cafes-en-situation?highlight=shoote

In French bars (out of coffe specialists) it is generally admitted they do not use correctly their expresso machine, often all is provided by the bean provider, the grinder, the expresso machine, maintenance, the dosing is minimal, as 7g for a cup, sometime even the grinder is adjusted by the coffee retailer, meaning the bartender do not knows much in grind adjustment.

ALso there are some industrial providers as "cafe Henry" , that give absolutely awful coffee (and they are not allowed to take another brand)

I had an ex bartender (30 years in the trade) at home, making electricity installation actually (changed trade) I made him a coffe and he said I put way too much grind, he said "good but way too strong  "

Some use longer extraction times by personal taste, ranging from 30 to 45 sec, generally anyway to obtain small quantities in cup.


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## MWJB (Feb 28, 2012)

Olek said:


> I do not understand "strike rate "
> 
> The only ratio I use, because it is simple, is grams in basket vs grams in cup so it can be from 1.5 to 2.5 or 3:1 at times.
> 
> ...


 Strike rate - say you make 10 good shots with different beans, many shots does it take? 10, 15, 20?

That's quite a spread of ratios, how do you know which to aim for when you pick up a bag.

Extracting more "fruit/flower/acidity" in different portions? Sounds like you are attempting to describe getting certain components to queue jump others in extraction. There's no evidence that this can be done for a reasonable range of extraction.


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## Olek (Aug 21, 2019)

I am deeply sorry but still I do not understand .

DO you mean in seconds of extraction time ? or the number of shots before my grinder is adjusted ? It is actually less than 10 generally more less than 5, with the same basket, same temperature (manually adjusted, even during the shot)

I heard some need only 2 shots to find the good regualation, sometimes I am lucky but it is refined anyway for the 5 first ones probably (and with lighter roasts I experiment a lot because I am not fan of high acidity)

I have no real problems with Italian type blends, more with lightly roasted coffes that seem to appreciate larger quantities in cup and basket or longer extraction time. But I am a beginner in expressos, it dates may that year that I baught the equipment, and it took me about one month to obtain enjoyeable expressos (with fresh beans at that time)

I have no much experience in very short extraction time, as I keep those 23 28 secs as a given (unless by chance I discover something good with 40 secs, as it happened) WHat you told me about brew ratios and 2 moments where the smoothness may develop interest me. Bu I wait to receive at least a new Passacqual cremador bag hopefully recent, to make tests.

Modifying pressure during extraction may allow to "push" certain extraction portion more than other.

For instance pre infusion may make the first part more efficient, raising soon to the max get aromas, and lowering at the end avoid astringncy..?


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## MWJB (Feb 28, 2012)

Thanks, I meant number of shots before grinder & ratio are adjusted.


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## Olek (Aug 21, 2019)

I find the Powerpoint version of the presentation , with all graphs it is much more readable.

https://static1.squarespace.com/static/584f6bbef5e23149e5522201/t/5cde81922ef0d000011ffe33/1558086049914/Tracking_extraction_v8_red.pdf

I have a guess that the "local" (Switzetzerland) influencing the data

For instance, extraction times are cut at 20sec (so wedo not know what happens in the 8 last)

The blends are 40% robusta , this may be a little high, I generally see 20-30% (in fact most of the coffee sold here is "pure arabica")

Here is the graph with time, the last ones

I seem to see 3 parts appearing


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## MWJB (Feb 28, 2012)

Olek said:


> I find the Powerpoint version of the presentation , with all graphs it is much more readable.
> 
> https://static1.squarespace.com/static/584f6bbef5e23149e5522201/t/5cde81922ef0d000011ffe33/1558086049914/Tracking_extraction_v8_red.pdf
> 
> ...


 I don't see these 3 parts?

I see a pretty uniform progression of chlorogenic acids & caffeine (though the caffeine extracts faster at the beginning).

The time specifically is not critical, assuming the level of extraction is there.


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## Olek (Aug 21, 2019)

MWJB said:


> I don't see these 3 parts?
> 
> I see a pretty uniform progression of chlorogenic acids & caffeine (though the caffeine extracts faster at the beginning).
> 
> The time specifically is not critical, assuming the level of extraction is there.


 I see 2 parts mostly . Do you think "oils" are concentraced acids ? "time" would mean there is some sort of cooking of the grind (and temperatures are high from basket to water, so there can be a transformation due to heat is not it ?)


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## MWJB (Feb 28, 2012)

Olek said:


> I see 2 parts mostly . Do you think "oils" are concentraced acids ?


 Oils are non-dissolved, they don't contribute to extraction (just dissolved material). They're in the drink (as part of total solids), especially unfiltered coffee like French press & espresso (filter coffee has negligible oils), but they're not particularly tasty in their own right.


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## Olek (Aug 21, 2019)

MWJB said:


> Oils are non-dissolved, they don't contribute to extraction (just dissolved material). They're in the drink (as part of total solids), especially unfiltered coffee like French press & espresso (filter coffee has negligible oils), but they're not particularly tasty in their own right.


 Thank you, I believe they have some value in the taste is not it ? I have a little hard time to envisage, as for a cooking recipe, that "time is not critical" (while I understand your point indeed)


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## MWJB (Feb 28, 2012)

Olek said:


> Thank you, I believe they have some value in the taste is not it ?


 Mostly to mouthfeel/body.

They can't have that much value otherwise filter coffee wouldn't taste good. Most analysis seems more focussed on chlorogenic acids (CGAs), trigonelline, caffeine, sometimes tannins.


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## Olek (Aug 21, 2019)

Thanks, they are what gives the "sirup like" aspect expected at the start of the extraction I suppose.


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## Olek (Aug 21, 2019)

Olek said:


> There is a phase of low extraction that can be sweet but simple flavour (about 12-14%), before you get into the sour/tart region. Get past the sour/tart region (maybe over 17-18%) and you get sweetness coming back again, but with ripe fruit acidity.


 are those % percentage of total extraction (vol. or time ) ?


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## MWJB (Feb 28, 2012)

Those are % of the mass of the dose that is dissolved in the cup. AKA extraction yield.

So 13% of an 18g dose would be 2.34g of dissolved coffee in the drink. It's a bit involved & expensive as to how you measure this, but you can also track the changes in extraction by keeping grind & dose the same & pulling longer & longer shots and noting the change in flavour.


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## Olek (Aug 21, 2019)

THANKS .This is not something I have access to then .I begin to wonder if strong pressure is not better anyway with small grind quantities ( assuming the pressure push the puck to the bottom of basket. )

I was told recently that opv was set to 9 for 2 cups and 9.5 for one cup basket. ( from a reputed brandit of expresso machines)

What happens often if I use 9g is that when I moisten the puck (very low pressure) it loose stiffness and it is disturbed too easily when the pressure is raised fast to 9.b .(I stop pump,turn the knob then push the button,the flow begin normally at 4 5 seconds but the puck is always muddy in the end) this problem do not arise with 2 cups baskets

Still in plumber questions, see 

I added the redistance to the dimmer and it regulates more linear and smooth.

Those yeld% relate in a way to extraction time (sort of inverse logarythmic curve) the ones you give me with those 2 "sweetness zones" are not later than the midfle of the shot if I understand correctly. ?


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## Olek (Aug 21, 2019)

Dimmer , on ULKA up5 , and parallel mounted resistor. the resistor change the control, low pressure is easy to obtain. I left some water going out, not really much as it was soon too much with high pressure. no mounting of the mano on a T at the moment, but I will.

I see the OPV activated when 8.5bar are going out of the pf. May be that mean , if one want 9bar on the puck, regulate the opv at 10,5 (?)


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## lake_m (Feb 4, 2017)

Surely you mean a resistor 'in series' to the pump? Parallel would be a straight short live to neautral?


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## Olek (Aug 21, 2019)

No I was said // the resistor is 25W, 3,3 Kohms . the goal is to allow the dimmer to respond better at low voltage.

What part of the pump would be in trouble ? the magnet ?


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## ashcroc (Oct 28, 2016)

lake_m said:


> Surely you mean a resistor 'in series' to the pump? Parallel would be a straight short live to neautral?


It won't short as the resistor is causing erm... resistance in the circuit. It's wired up the same way if converting motorbike indicators from bulb to led (unless you change the flasher unit instead).


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## lake_m (Feb 4, 2017)

ashcroc said:


> lake_m said:
> 
> 
> > Surely you mean a resistor 'in series' to the pump? Parallel would be a straight short live to neautral?
> ...


 So in effect the resistor is further dropping the available power to the pump after the dimmer in circuit.


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## ashcroc (Oct 28, 2016)

lake_m said:


> So in effect the resistor is further dropping the available power to the pump after the dimmer in circuit.


Yes but since most pumps will happily run well over 9 bar at full power, it's not really a problem dropping it's capabilities a bit to get lower end control.


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## Deidre (Aug 13, 2019)

What number of bars of pressure does the older londinium deliver?


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## Mrboots2u (May 10, 2013)

Deidre said:


> What number of bars of pressure does the older londinium deliver?


 peak of 7 to 8 bar


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## Deidre (Aug 13, 2019)

@Mrboots2u Excellent information & video illustration!

Somewhat off topic, but seeing the temperature cycle brings to mind another question: if one wanted to reduce the brewing temperature, is there a way (or a work-around strategy) to do this?


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## Mrboots2u (May 10, 2013)

Deidre said:


> @Mrboots2u Excellent information & video illustration!
> 
> Somewhat off topic, but seeing the temperature cycle brings to mind another question: if one wanted to reduce the brewing temperature, is there a way (or a work-around strategy) to do this?


 Not sure? Why woudl you want to reduce it tho?


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## Deidre (Aug 13, 2019)

Mrboots2u said:


> Not sure? Why woudl you want to reduce it tho?


 Just thinking there might be a benefit, with a medium-dark roast, to shoot for 91/92C at the start of the extraction (vs 96.5 C).


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## Deidre (Aug 13, 2019)

If I've got that wrong, don't hesitate to tell me.?


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## Mrboots2u (May 10, 2013)

Deidre said:


> Just thinking there might be a benefit, with a medium-dark roast, to shoot for 91/92C at the start of the extraction (vs 96.5 C).


 guide your extraction and taste by brew ratio and grind adjustment, which you can measure. trying to drop 1c for a bean isnt going to be repeatable or necessary with a medium roast.

usa forums tend to talk alot about dialling in by temp but in my personal experience only, i haven't changed temp on a machine for years.

not saying your wrong but there are other easier and quicker ways of driving extraction.


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## ajohn (Sep 23, 2017)

Deidre said:


> Just thinking there might be a benefit, with a medium-dark roast, to shoot for 91/92C at the start of the extraction (vs 96.5 C).


 Perhaps they are using HX machines and playing with the service boiler temperature. Maybe grouphead temperature as well somehow.

It could give a difference. For instance my Sage DB blonds almost immediately. I used a Picino which ok is dual boiler but mechanical thermostat. That blonded much later on. I put that down to water being initially well over 93C. The Sage uses pre infusion and what comes out during that is very dark but the Picino produced a much larger volume of it. Taste was different but I wouldn't say what came out of the Picino was bad.

Personally I'd suspect that people who do this are part of the I have a 20g basket and use a 1 to 2 ratio brigade. In practice other weights can be used and ratios can be higher or lower. There is a lot of taste variation that can be obtained that way.

John

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## Deidre (Aug 13, 2019)

I may have been blaming the wrong thing for flavour differences. Am I completely wrong in thinking the shots taste differently when made right after I have pulled some water through the grouphead to clean the portafilter & basket from the previous shot? I was attributing that change in taste to the increased heat in the grouphead from pulling a short pf cleaning flush (and then thought perhaps I should clean the pf in the sink rather than flushing it in the grouphead, to avoid any overheating of the next shot).


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## ajohn (Sep 23, 2017)

I've not used a HX machine yet but will be shortly. Dual boiler with PID yes and also one with a mechanical thermostat plus a tiny boiler.

Really I don't think it's possible to answer that question without details of the machine you are using. There are various types. In all cases though most machines are usually left on until the grouphead is fully heated with the portafilter in to heat that as well. Then a flush to get internal parts up to temperature. On conventional machines that is likely to take 1/2hr. Some longer.

John

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## Mrboots2u (May 10, 2013)

Deidre said:


> I may have been blaming the wrong thing for flavour differences. Am I completely wrong in thinking the shots taste differently when made right after I have pulled some water through the grouphead to clean the portafilter & basket from the previous shot? I was attributing that change in taste to the increased heat in the grouphead from pulling a short pf cleaning flush (and then thought perhaps I should clean the pf in the sink rather than flushing it in the grouphead, to avoid any overheating of the next shot).


 A quick flush shouldn't impact on your group head temp that much ( depends on quick) it's a bit lump of metal and the group should stabilise pretty quick. Of course depends on your definition of short. Don't take this the wrong way but I have sen 100's of threads over the yers of people saying first shot tastes better or worse than the second , often it's down to the human as well as the many variables taken to make one ( presuming you are weighing in and out )

@coffechap can answer this, but you used to be able to pull higher and lower temps by choosing when to pull on the heating cycle on the old L1s? It's a long time ago though am I could be mistaken ( quick steam purge ? )

The beauty of the l1 is are they are temp stable and no fuss. id use that you advantage as a constant rather than trying to adjust temp on the fly (its a big group head remember storing that heat ) adjust your shot in taste by grind and brew ratio so you can repeat it. Unless you are using a uber uber light roast where all else has failed to extract sweetness then id use temp as the last thing. Don't think you are in that place.


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## ajohn (Sep 23, 2017)

I thought it was a Londinium from other posts. They seem to suggest a 1hr heat up and once that's done it looks after itself and temperature will be stable.

John

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## Mrboots2u (May 10, 2013)

ajohn said:


> I thought it was a Londinium from other posts. They seem to suggest a 1hr heat up and once that's done it looks after itself and temperature will be stable.
> 
> John
> 
> -


 its is and 1 hour is a good suggestion for getting the group up, unless you wanna flush a ton of water through


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## Olek (Aug 21, 2019)

The only soluce I find with a single boiler is to have a thermometer probe at the bottom (external wall indeed)of the boiler, and manage the starting temperature by heating with the "vapor" button . It is possible on my simple Reneka may be not on more evolved machines.

So for instance I heat up to 96 and keep the button inserted while the extraction goes, which make about 2 deg less in the end . If I do not heat during shot the loss is about 5 6 degree depending of the room temperature I guess.


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## Deidre (Aug 13, 2019)

You are quite correct, no uber light roasts here! ? No oily dark roasts either, but I am certainly leaning to the darker end of the roast spectrum with the medium-dark I am using.

I am weighing beans and stopping the shot by gauging both the shot weight, and also by the colour change/blonding &/or the decrease in rich flow. I have been trying to use a finer grind to allow for longer preinfusions (10 to 20 seconds), prior to pulling the shot. Is this a bad idea?

I am using the older version of the Londinium 1, and perhaps should approach it without my past history, as this is a very different machine. I did find in the past I had better flavour (sweeter) with slightly lower brewing temperatures. But, yes, so many variables in espresso making (& the human), it can be difficult to know for certain regarding cause & effect.

As far as quick cleaning the pf flushes, would a 3 or 4 second pull on the lever (or the equivalent of a mug of water) affect the shot brew temperature at all?


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## Mrboots2u (May 10, 2013)

Deidre said:


> You are quite correct, no uber light roasts here! ? No oily dark roasts either, but I am certainly leaning to the darker end of the roast spectrum with the medium-dark I am using.
> 
> I am weighing beans and stopping the shot by gauging both the shot weight, and also by the colour change/blonding &/or the decrease in rich flow. I have been trying to use a finer grind to allow for longer preinfusions (10 to 20 seconds), prior to pulling the shot. Is this a bad idea?
> 
> ...


 If you are going to use a brew ratio to help pull a shot then IMHO use a brew ratio. Trying to stop it by weight, colour and stream are all pulling you in different directions, in my experience. If you are going to use blonding and flow stop it by that, if you are going to use a brew ratio do that. Up to you which one, but trying to mix and match is going to pull you in different ways. Blonding is not a consistent thing across all beans, different origins and roasts shoe different colours at a pour for example/

How long you want to pre infuse for is up to you, the longer you pre infuse the more likely it is to flow a bit quicker when full pressure hits the puck which is why trying to stop by flow and weight out can be fighting against each other. The longer you pre infuse the finer you may have to grind , this is not a bad thing, just a statement .

3 or 4 second flush shouldn't hit the brew temp too much .


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## Deidre (Aug 13, 2019)

Mrboots2u said:


> the longer you pre infuse the more likely it is to flow a bit quicker when full pressure hits the puck


 With this in mind, when aiming for a more syrupy shot, would a longer preinfusion help or hamper, or not really be a factor?

And, will follow your advice; I'll stick with brew ratio.?


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## Mrboots2u (May 10, 2013)

Deidre said:


> With this in mind, when aiming for a more syrupy shot, would a longer preinfusion help or hamper, or not really be a factor?
> 
> And, will follow your advice; I'll stick with brew ratio.?


 Syrupy as in thickness and strength , I'd be wandering towards a shorter brew ratio .

Re Preinfusion have a play , I am not one for shorter thicker shots myself, but gloop tends to come from a tighter brew ratio, tighter grind, a long pre infusion if not balanced by a sufficient grind could leas to a quicker shot , less mouthfeel. But I am being guessing.

Perhaps wait until you see some beading over the baskets than drop the lever? Taste see how it comes out?


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## ajohn (Sep 23, 2017)

Some people use a brush to clean the portafilter. Maybe a quick spurt out of the hot water outlet would be the best option for washing it if needed. Personally I prefer pucks to come out cleanly  and am struggling a bit with that at the moment but down to where residue wouldn't cause any problems with another shot but I brush it out into the knock box.

I drink all sorts over time but tried an extremely oily one early on and it suites my wife if I go risteretto by cutting the shot time.

John

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