# Any guidance for Yirgacheff?



## earthflattener (Jul 27, 2015)

Hi folk,

I'm trying @Coffee by the Casuals Yirgacheff at the moment. I've tried two very different espresso recipes and a couple of mildly different V60. I'm definitely enjoying it but wonder if I could do better.

I'm using a Niche Zero and a Sage dual boiler

1) I started with what I guess might be something of an extreme recipe, simply because I was converging towards something like this in my last coffee.

- temperature to 95C

- pre-infusion set to 90 secs @ 60% which means that the entire extraction is at 6.5 to 7 bar

- 18g / 42g/ 55 secs

Feels quite well balanced, delicate by espresso standards at least. Pleasant acidity. I like it. I can't say I'm getting the tasting notes - but not sure I ever do.

2) Then, I thought I should try something more standard.

- temperature 93C

- preinfusion back to the standard, i.e. 7 secs at 60% followed by full pressure 9 bar

- 18g/42g/50 secs

This was definitely sour. Had to put it into a cortado to drink it, though I personally don't think this goes too well with milk in any case.

So, I did get something that I quite liked with the 1st recipe, but I've seen people recommending starting with something more standard, hence the 2nd recipe. Is there another way to modify a standard recipe that might move me in the right direction - maybe making the fruit be a little bit clearer?

For the V60, I've followed Hoffman's recipe. Tried with Niche at 50, then at 65. First case was a little bit astringent. Second was not at all, but maybe I pushed it too far as it was slightly muted. I will probably just go between the two (maybe 57) later today unless someone has better suggestions.


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## Coffee by the Casuals (Sep 15, 2020)

Hey @earthflattener - sounds like you're doing some good experimentation here.

I'm going to grab a bag off the shelf tomorrow when I'm the roastery and I'll see what I can come with for you.

Before I do: what Niche number are you at for espresso?


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## earthflattener (Jul 27, 2015)

For the 1st one, I was at 17.

For the 2nd one....err, I didn't write it down😱, I suspect it was 16 - but certainly within 15-17.

Tried the V60 at Niche 57 this afternoon. It seemed like a good balance, enough acidity but not at all sour.


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## Rob1 (Apr 9, 2015)

You would be lucky to get florals out, especially if they are subtle, with a conical grinder. You'll might get a hint. Shouldn't be a problem with fruit notes really. You could try something even more extreme: 18g:80g in 60-70 seconds (you'd only get to about 6 bar with this as the coffee wouldn't be ground finely enough to generate resistance). I found 'shots' like that interesting but really not espresso anymore.

Probably better to coarsen your grind a few notches and run the standard profile again to see where you are.


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## earthflattener (Jul 27, 2015)

I do 2 espressos in the morning, so I'll try both of these. I can lower pressure just a little more (I can see myself wanting a machine that pressure profiles at this rate....and a big flat!)


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## TomHughes (Dec 16, 2019)

Interesting on the temp. 
I am finding that fruity floral coffees are definitely better when I am extracting at 95ish.

Plus bear in mind that the water might be coming in at that temp, but once it hits the coffee and heat is dragged out by the mass of the PF and other metal bits then it could be down in the low 90s.

I have often suspected that this is why my old DTP produced fine shots on dark roasts but terrible on a light roast. I suspect the coffee was only being extracted at high 80s max. This isn't going to cut it for a light roast.

I also suspect that some of the higher end machines that take a long time to build temp, then thoughly heating the PF can often produce an extraction at closer to what the machine is saying, whereas most people don't fully warm everything enough to get this.

So I reckon when you were at 95 you were probably extracting at 92-93 and when at 93 it was more like 90.


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## earthflattener (Jul 27, 2015)

Sounds plausible. With the Sage db, it claims that you are up to temperature quickly, but I always leave it about 20 minutes and run water through the head, but still, I have no way of verifying temperature.


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## earthflattener (Jul 27, 2015)

Rob1 said:


> You would be lucky to get florals out, especially if they are subtle, with a conical grinder. You'll might get a hint. Shouldn't be a problem with fruit notes really. You could try something even more extreme: 18g:80g in 60-70 seconds (you'd only get to about 6 bar with this as the coffee wouldn't be ground finely enough to generate resistance). I found 'shots' like that interesting but really not espresso anymore.
> 
> Probably better to coarsen your grind a few notches and run the standard profile again to see where you are.


 So, the second option just made it more sour. Not really a success

The first one was interesting. I didn't go quite as far at 80g out. In fact I only went to 58g (roughly 65 secs). I split it, so that I put in a small cup and removed the first cup at 42 out and collected another 16g. Tried both separately then combined. So the 'shot' taken from 42-58 was clearly weak, but not at all bitter, so seems clear that you can push this coffee quite long. The combined was quite good. Unfortunately, I had reduced the pre-infusion pressure to 55% which is the minimum I can go on the Sage. This brought the head pressure down to only about 3.5 bar, so it is quite non-linear..

I'm running out, but I'll try the full 80g out tomorrow, but push the pressure back up.

V60 at Niche 55. Spot on really. So at least I cracked the pour-over to my satisfaction.


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## Rob1 (Apr 9, 2015)

Why did you reduce pre-infusion pressure? Without a grind to suit the pressure you're basically running at very low flow rates. It sounds like you're grinding too fine generally. Anyway 55% sounds like actual pre-infusion whereas the 60-70% is too high for pre-infusion really. Sorry just realised I didn't mention coarsening the grind for the 80g yield directly I just said something about it not being able to generate resistance...


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## jaffro (Oct 6, 2015)

I have some of the yirg at home. Haven't tried it as spro yet, but I'll try tomorrow and let you know thoughts. It'll be on standard MaraX preonfusion but I'll try at a few different temps and see where I get to.

For v60 and December I've been getting best results at about the right hand hinge on the Niche. 15:250, 50g bloom for 45 secs, then 2 pours of 100, first starting at 45 secs, second starting at 1:30. On v60 it comes in at about 3:20 to 3:30 usually. On December I've been closing it off for the bloom, then opening it all the way from 30 seconds onwards, but all in its more like 4 mins or a smidge over. Both taste really similar if I'm honest haha.


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## earthflattener (Jul 27, 2015)

jaffro said:


> I have some of the yirg at home. Haven't tried it as spro yet, but I'll try tomorrow and let you know thoughts. It'll be on standard MaraX preonfusion but I'll try at a few different temps and see where I get to.
> 
> For v60 and December I've been getting best results at about the right hand hinge on the Niche. 15:250, 50g bloom for 45 secs, then 2 pours of 100, first starting at 45 secs, second starting at 1:30. On v60 it comes in at about 3:20 to 3:30 usually. On December I've been closing it off for the bloom, then opening it all the way from 30 seconds onwards, but all in its more like 4 mins or a smidge over. Both taste really similar if I'm honest haha.


 Right hand hinge corresponds to what I call 55 (if I've measured it right), so it sounds like we are full agreement on grind. I'm doing 20:340, so pretty close on dose. It also comes out in about 3.20-3.30.


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## earthflattener (Jul 27, 2015)

Rob1 said:


> Why did you reduce pre-infusion pressure? Without a grind to suit the pressure you're basically running at very low flow rates. It sounds like you're grinding too fine generally. Anyway 55% sounds like actual pre-infusion whereas the 60-70% is too high for pre-infusion really. Sorry just realised I didn't mention coarsening the grind for the 80g yield directly I just said something about it not being able to generate resistance...


 That's a very good question. I'm not 100% sure what lower pressure does exactly, but my feeling is that lowered pressure seems to delay extraction of the bittering components in the coffee. As I understand it, that the order of extraction is Acids&Fats, then sugars then plant extracts(bittering). Presumably it's not just temperature that controls the rates, but pressure also and each of the 3 will extract differently depending on P&T. I could be talking utter hogwash, but on the basis of my very limited experience, I 'feel' that the Acids& fats as well as sugars are accelerated more by higher temps than they are depressed by lower pressure, whereas relatively it is the other way round for the fibres. Now that is me overfitting a 'big theory' to a scant amount of evidence, but it is my working model until I find out what is actually going on.

I didn't really get what you meant about 'not generating resistance'. At standard 9 bar, it is still taking near enough to 40 secs, so if I 've understood you correctly, there is still a reasonable resistance. I'll try and look a bit more carefully at the pressure buildup tomorrow. I spend too much time admiring my new naked portafilter to more than note the value built up towards the end of the flow.


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## jaffro (Oct 6, 2015)

Just had a crack at a spro with the Yirg.

16:36 in 33 seconds. Middle setting on MaraX so 94 degrees (thought I'd start off in familiar territory). Standard pre infusion on MaraX, about 10 seconds (?) including the slow ramp up to 9 bar

Surprised how good this one came out. I can understand that floral notes may come out better on a flat grinder but this feels close. There's some nice acidity that I think might be the raspberry coming through, although I'm not quite sure what exact note I'd have come up with myself. Not perfect but not a bad start.

Think there's some scope for improvement in there. I might try one shot at same grind higher temp and one at the same temp but very slightly finer grind. Maybe a longer shot (16:40 or 44 maybe?). See what else comes out.


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## Rob1 (Apr 9, 2015)

earthflattener said:


> That's a very good question. I'm not 100% sure what lower pressure does exactly, but my feeling is that lowered pressure seems to delay extraction of the bittering components in the coffee. As I understand it, that the order of extraction is Acids&Fats, then sugars then plant extracts(bittering). Presumably it's not just temperature that controls the rates, but pressure also and each of the 3 will extract differently depending on P&T. I could be talking utter hogwash, but on the basis of my very limited experience, I 'feel' that the Acids& fats as well as sugars are accelerated more by higher temps than they are depressed by lower pressure, whereas relatively it is the other way round for the fibres. Now that is me overfitting a 'big theory' to a scant amount of evidence, but it is my working model until I find out what is actually going on.
> 
> I didn't really get what you meant about 'not generating resistance'. At standard 9 bar, it is still taking near enough to 40 secs, so if I 've understood you correctly, there is still a reasonable resistance. I'll try and look a bit more carefully at the pressure buildup tomorrow. I spend too much time admiring my new naked portafilter to more than note the value built up towards the end of the flow.


 What bittering components are those? Chlorogenic aid and caffeine are the main contributors of bitterness aside from the fibres of the bean itself which will be extracted through the shot as fines get washed into the cup. If you grind coarsely you'll get fewer fines and using a lower pressure allows you to grind coarser. Caffeine is extracted early along with acids and fatty acids. I don't think it's really useful or even accurate to think of extraction as occurring in stages or at different rates. Splitting shots is fairly useless in my opinion. Pressure and flow rate are dependent on grind, you can't have a high pressure with a coarse grind as there will not be enough resistance (high flow rate, low pressure extraction) but if you use a fine grind and lower the pressure by an OPV, software or flow paddle, then you will essentially adjust flow rate to achieve low pressure (low flow, low pressure). Low pressure and low flow will need a higher temperature for the shot as temperature is lost through the portafilter and coffee puck. I'm fairly certain both low pressure and low flow rate will lower extraction.


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## earthflattener (Jul 27, 2015)

@jaffro. I went to your V60 setting of 15g in and 250 out - simply because I'm running out of this coffee. Preferred it to my initial ratio. Finally getting floral notes...Niche conical burrs notwithstanding.

@Rob1 I don't know what the bittering components are, so I need waaaayyyy more research before I know enough to speak with any authority, but I did read today that caffeine is about 10-15 of the total bittering. I really can't speak to extraction of coffee in a 30sec timeframe, but from basic physics, any multiphase fluid does phase transitions at different locations on the phase (PVT) diagram (sorry for the nerdy/pretentious tech speak, but it kind of is my day job). So for example, each phase in a multiphase oil in porous rock media interacts with the driving/injected fluid (water, steam or gas depending on the type of oil) in a different way. Usually lighter compounds mix with the injection fluid more easily with heavier compounds needing more energy to become mobile. This will also happen with coffee - although maybe not in time frame of a brew. The grind drives grain size and permeability, which as you say affect flow rate, but also the surface area of coffee in contact with the water, so do affect extraction, as extraction only happens at the interface between them, but both heat and pressure 'should' affect the rate at which coffee components in contact with the water dissolve. As I had said in earlier post. I don't know that it is relevant in the time frames that we brew in - but it is a basic physical law that it matters over 'some time frame'. So yeah, (the gradient of) pressure linearly affects flow rate (Darcy's law) and the rate is a function of the compond, but whether it does so differently per compound in a 30sec time frame....well, that is not so much a question of physics principle and more an empirical question.....that you are in a far better position to answer than me.


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## theCoffeeDeveloper (Sep 30, 2020)

Really interesting experimentations. Ready through the entire topic. But one thing I can't understand but maybe it's. Sage DB thing. 55sec for a espresso would make mine taste crazy sour/salty even. I never go beyond 30/32 with 5 sec preinfusion.

Sent from my iPhone using Tapatalk


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## Rob1 (Apr 9, 2015)

theCoffeeDeveloper said:


> Really interesting experimentations. Ready through the entire topic. But one thing I can't understand but maybe it's. Sage DB thing. 55sec for a espresso would make mine taste crazy sour/salty even. I never go beyond 30/32 with 5 sec preinfusion.
> 
> Sent from my iPhone using Tapatalk


 Are you talking about using this specific bean with the same pressures and yields and the same grinder or are you talking built in grinder and different beans?

I can definitely get sour/salty when I go to extremes but also can get really good concentrated flavours and only have a bad after taste, which I then adjust away from.


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