# Preinfusion on the L1



## aaronb

Has anybody been playing around with this recently, in particular with lighter roasts?

I've been pretty consistent with 3-4 secs, as it works for me and avoids having to do a flush just in case of thermosyphon stall.

Just wondered if im missing out by not playing with extended preinfusions though?


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## sjenner

I usually pre-infuse for about the same as you Aaron...

Reiss has compared long pre-infusions to drip/filter coffee since longer pre-infusions cause the grinds to "bloom" rather than merely "wet". I seem to remember that many early users were doing all sorts of pre-infusions, the original official advice was for around 5 seconds, which is nearly twice as long as 3, but many were doing 10 and 15 seconds.... waiting for the first drops....

But definitely a worthwhile experiment, depending of course on whether the experimenter can discern subtle differences through the fog of cigarette smoke.


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## stevogums

TBH I have been sticking to 8 secs pre infuse on everything.

However i have gone a s far as 16 secs on some blends just to experiment,did give somewhat mixed results so i returned to my 8 secs as advised by a few people.

Never really tried lower scale 3/4 secs but i will now just to see.

Haven't had the L1 that long so im trying to be disciplined in my variants.

(Just out of curiosity what does the stalling of the thermosyphon look and sound like? any videos and what damage does it do?)


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## The Systemic Kid

stevogums said:


> (Just out of curiosity what does the stalling of the thermosyphon look and sound like? any videos and what damage does it do?)


Doesn't do any damage - stalling the thermosyphon is caused by air getting into the loop which interupts the gentle but necessary brew water circulation. - As a result, water temp drops which is noticeable two ways. Your shots will taste more sour due to under-extraction and the group, which acts as a massive heat sink, will become cooler to the touch. To rectify stalling, you have to bleed the system.


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## aaronb

If you touch the group for more than 2 seconds and dont go "ow!" then you have stalled the thermosyphon









I've restarted it just by doing a couple of quick flushes, then leaving it to do it's thing before.


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## lespresso

i don't wish to contradict you but it is not correct that you have to bleed the system - ever

i don't even know what you mean by the phrase 'bleed the system' - its not a hydraulic brake system

if you rinse the group (after you have emptied the basket after each shot) by pulling the lever down for no more than an instant to release 50-60mL of water (and you might as well have the empty PF loosely in the group whilst you do it and jiggle it around to dislodge any stray grounds and gunk) the thermosiphon will never, ever stall

if you forget to do a rinse after your shot it is true, the thermosiphon will stall pretty much every time and you will know this as you will be able to place your hand on the group and you will be able to keep it there as the group surface temp will drop down to about 60C

the remedy is the same: a 50-60mL rinse just to break the air lock

you will then have to give it 5 minutes or so for the thermosiphon to bring the group back up to temp

it is a very simple design that will make great espresso for decades

if you want buttons to fiddle with don't buy it - this machine was designed to provide an antidote to the vast array of machines already in the marketplace that are engaged in a feature war

reiss.


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## Orangertange

This is a interesting one, I do about a 10 to 12 sec pre infusion with 18gs/ but only really drink dark roast on l1 maybe will try cutting back down a bit


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## lespresso

the lighter the roast, the longer the pre-infusion

if you like a chimney sweep, i mean traditional italian, roast then cut the pre-infusion back to 3 or 4 seconds (and drop the dose i think into the 14-16g range)

if you are running super light roasts then you will need to wind the dose up to about 18g and lengthen the pre-infusion, perhaps as far as 15 seconds in some cases

you can make life easier for yourself by stabbing the steam wand to trip the element on and wait for the element to turn off (red light off) and then pull the lever down. this ensures you are pre-infusing with the most amount of pressure that the system can deliver during pre-infusion, i.e. around 1.3 bar

best

reiss.


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## stevogums

lespresso said:


> i don't wish to contradict you but it is not correct that you have to bleed the system - ever
> 
> i don't even know what you mean by the phrase 'bleed the system' to be honest - its not a hydraulic brake system!
> 
> if you rinse the group (after you have emptied the basket after each shot) by pulling the lever down for no more than an instant to release 50-60mL of water (and you might as well have the empty PF loosely in the group whilst you do it and jiggle it around to dislodge any stray grounds and gunk) the thermosiphon will never, ever stall
> 
> if you forget to do a rinse after your shot it is true, the thermosiphon will stall pretty much every time and you will know this as you will be able to place your hand on the group and you will be able to keep it there as the group surface temp will drop down to about 60C
> 
> the remedy is still the same: a 50-60mL rinse just to break the air lock
> 
> you will then have to give it 5 minutes to bring the group back up to temp
> 
> it really is this simple - there are no secrets or voodoo
> 
> anything else you have read to the contrary is simply incorrect, which is why i have reluctantly made this post
> 
> it is a very simple design that is makes great espresso for decades
> 
> if you want buttons to fiddle with don't buy it - this machine was designed to provide an antidote to such machines
> 
> sorry for butting in, but sometimes something has to be said as it becomes adopted as fact because someone read it on a forum
> 
> reiss.


I do rinse the basket after knocking the puck out via pulling the lever down for an instant so i should never stall which is good.

Thanks for explanation including the pre infusion advice ..


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## Orangertange

Cheers Reiss,

and good tip about the steam, will give it a try, consistancy is king and all that,


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## mcharrogate

I'm very new to the world of the L1, and indeed levers, but with lightish roast (extract Dr strangelove, which as it happens I'm very impressed with) I'm dosing 18g into an 18g vst with a 6-8 second preinfusion and that seems to be working really well for me. Generally letting the shot run a little longer (around 35 seconds from 1st drip) than i would previously have done with my old gaggia classic and getting about 32g out, lovely texture and balanced acidity.


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## The Systemic Kid

Running extractions at 1:2 ratio is better for lighter roasts which are more prone to under extracting. Grind as fine as you can and tamp light.


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## Mrboots2u

lespresso said:


> the lighter the roast, the longer the pre-infusion
> 
> if you like a chimney sweep, i mean traditional italian, roast then cut the pre-infusion back to 3 or 4 seconds (and drop the dose i think into the 14-16g range)
> 
> if you are running super light roasts then you will need to wind the dose up to about 18g and lengthen the pre-infusion, perhaps as far as 15 seconds in some cases
> 
> you can make life easier for yourself by stabbing the steam wand to trip the element on and wait for the element to turn off (red light off) and then pull the lever down. this ensures you are pre-infusing with the most amount of pressure that the system can deliver during pre-infusion, i.e. around 1.3 bar
> 
> best
> 
> reiss.


Am i right in thinking you are also pulling the shot a a slightly higher temp here ( as you might want to do with a lighter roast to aid extraction )

Comment is based on pulling a few shots at different pstat settings with a scace btw...


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## aaronb

I've been doing what Reiss suggests since the first week as part of my routine (probably from him suggesting it to me at the time!)

Load basket, quick tap on the steam arm, wait for element to click off then lock pf and pull lever.

I did experiment with letting the pstat go to its lowest then pulling the shot but found the results murky.


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## lespresso

Mrboots2u said:


> Am i right in thinking you are also pulling the shot a a slightly higher temp here ( as you might want to do with a lighter roast to aid extraction )
> 
> Comment is based on pulling a few shots at different pstat settings with a scace btw...


If you stick thermocouples on the outside of the group and just let it sit there you can see the 'heartbeat' of the group if you like

ie the temperature movement as a result of the pressure range in the system between the pressure switch turning the element on at the lower limit and turning the element off again at the upper limit

I can't remember the exact temp movement observed - I have the data here somewhere, but i recall the value being about 0.1C, or in other words, nothing to worry about given the pressure switching range is about 0.2 bar

Flicking the steam wand is simply to get a little more pressure to pre infuse with, especially for larger doses. The thing that goes hand in hand with it obviously is not to tamp too hard or else the water will take forever to work it's way through the puck

Reiss.


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## fluffles

I recently had issues with the lever catching too high when releasing the lever. I read up on this and it was recommended by many to increase pre-infusion time. This seems to have remedied the issue, so I now time around 7s pre-infusion for a 15g dose and up to 9s pre-infusion for 17g dose. I believe darker roasts need less in the way of pre-infusion.

Not sure of the reason for the relationship between pre-infusion and the point at which the lever grabs - can anyone explain? What is the ideal point for it to grab (mine is still above 45 degrees for example.)

fluf


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## lespresso

fluffles

your seals need replacing if thats the case. its a sub 20 minute job. if you want me to step you through it call me on Skype or FaceTime - around most of the time other than UK afternoons


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## aaronb

That seems odd, I never have issues with 18g dose 3 sec preinfusion with lever locking too high.

Edit: Reiss already diagnosed it


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## fluffles

at what point should it typically grab?


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## Mrboots2u

Where the lever grabs will be effected by a couple of things

- how good the seals are and how well lubricated the parts are

- dose ( how much )and how fine the grind


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## lespresso

fluffles said:


> at what point should it typically grab?


at 45 degrees above horizontal, or 10:30 as some prefer to call it

if you are tamping too hard this won't happen, for as soon as the load of the spring is applied to the water it will disappear into the unsaturated puck

if your seals have been slightly damaged they will let air past (not water) and so that will also result in the lever getting to about the 11am position before it is arrested by the resistance of the puck - this damage is so slight that you will not detect it with a visual inspection

I've had my seals in for a year and they are still going strong - if they are damaged it is typically in transit on a new machine or initial fitment, rather than the result of wearing out


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## fluffles

Hi,

Replaced the seals on Friday and it has been faultless since then - thanks for your suggestions.

I've just read some posts further back on this thread and can anyone explain the logic why lighter roasts need a bigger dose? Still can't get my head round it, won't this only encourage further under-extraction?


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## aaronb

fluffles said:


> Hi,
> 
> Replaced the seals on Friday and it has been faultless since then - thanks for your suggestions.
> 
> I've just read some posts further back on this thread and can anyone explain the logic why lighter roasts need a bigger dose? Still can't get my head round it, won't this only encourage further under-extraction?


I've just found that an 18g dose of a lighter roast tastes a lot better than a 16g one.

Try it yourself, and see what works for you.

Why would it be under extracted?


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## lucasd

So for example on VST 18g basket, how big dose you would use for medium and light roast, respectively?

Or just stick to 18g?


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## Mrboots2u

lucasd said:


> So for example on VST 18g basket, how big dose you would use for medium and light roast, respectively?
> 
> Or just stick to 18g?


In an 18 g basket I'd go no more than 17- 18g personally. This leaves enough headroom for the coffee to expand ..


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## The Systemic Kid

lucasd said:


> So for example on VST 18g basket, how big dose you would use for medium and light roast, respectively?
> 
> Or just stick to 18g?


Recall Reiss recommending - for Londinium beans which are medium plus roast - dosing around 16grm - even a tad lower. This is not set in stone however. But for lighter roasts, certainly upping the dose a gram or two is a good idea to avoid under-extraction.


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## Mrboots2u

Lighter roasted beans will more than likely need a bit more water through them ( bigger brew ratio )

If you under extract one you could be depriving those bright fruit flavours of sweetness leading to percieved sourness of the coffee (this is under extraction )

Be careful if the dose is increased to the point where you run out of water in the group in one pull you won't be able to achieve this

If you up the dose and keep all else the same then you may end up under extracting even more..


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## pizzaman383

I don't have a Londinium but I'm a big fan of it and I have healthy respect for its temperature stability. When I got the opportunity to buy a dipper version of the CMA/Rossi spring-lever group I built a PID-controlled dipper machine.

I've been learning about how to brew good espresso and have been playing with different amounts of preinfusion. I think I've learned something interesting that I would like to add to this discussion. To aid in shot consistency I measure the group head temperature right where the water flows into the cylinder and this gives me a view into what's happening during preinfusion.

From what I see I think that the amount of time I allow for preinfusion directly impacts the starting temperature of the shot. I've begun stopping the preinfusion when the group head temperature reaches a specific number rather than stopping preinfusion after a specific amount of time. To my surprise, I can tell the difference in taste of a one-degree change in the temperature at which I start the shot.

Has anybody else noticed this relationship between the amount of preinfusion time and the group head temperature?


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## Mrboots2u

Hi pizzaman

when your pulling the shots , are you pulling each time with the pstat registering the same number....

Pulling at a higher pstat reading will result in a slightly higher extraction temp


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## pizzaman383

My machine is PID-controlled and doesn't use a pstat. I directly measure the group head and start the shot when the temperature reading from the group head is the same. Testing with my machine shows that a higher boiler temperature would need a shorter preinfusion time for the group to hit the same starting temperature. Similarly, a lower boiler temperature would need a longer preinfusion time to get the same group temperature.


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## mathof

pizzaman383 said:


> I don't have a Londinium but I'm a big fan of it and I have healthy respect for its temperature stability. When I got the opportunity to buy a dipper version of the CMA/Rossi spring-lever group I built a PID-controlled dipper machine.
> 
> I've been learning about how to brew good espresso and have been playing with different amounts of preinfusion. I think I've learned something interesting that I would like to add to this discussion. To aid in shot consistency I measure the group head temperature right where the water flows into the cylinder and this gives me a view into what's happening during preinfusion.
> 
> From what I see I think that the amount of time I allow for preinfusion directly impacts the starting temperature of the shot. I've begun stopping the preinfusion when the group head temperature reaches a specific number rather than stopping preinfusion after a specific amount of time. To my surprise, I can tell the difference in taste of a one-degree change in the temperature at which I start the shot.
> 
> Has anybody else noticed this relationship between the amount of preinfusion time and the group head temperature?


I used to do just that with my La Pavoni Europiccola. (I haven't bothered with my Londinium as I haven't had the same problem with temperature variance ruining shots.) As I understand it, the point of the grouphead on lever dipper machines is to act as a heat sink to reduce the temperature of the water which arrives directly from the boiler; it follows that the longer the water spends in the grouphead, the more heat it will shed.

Matt


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## pizzaman383

It seems to me that the group temperature first climbs a few degrees during preinfusion then stabilizes for a few seconds then starts dropping.


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## mathof

Yes, I've observed a similar phenomenon. I figure that as the boiler water sheds temperature to the heat sink, the group will naturally get hotter; next, the group itself will shed heat to the air and become cooler.


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## dsc

I know it's an old thread but I'll bump this as most likely there's a few more L1 users on the forum. What's your approach to preinfusion nowadays? I used to do a short 4-5sec preinfusion on all my shots, but today I dropped the lever and got districted which resulted in around 20sec of preinfusion and a great fruity note in a rather dark roasted blend I'm using now. Curious if this is from the low pressure soak at the start or a lower overall brewing temperature.

T.


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## Asgross

I like to wait until theres a couple of drops in the cup so regularly thats 15 secs just pre inf

Total time of pour can sometimes be 45sec

1:2 or 1:2.5


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## Snakehips

When I had my L1 I would typically pre-infuse for between 8 - 15 seconds.


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## mathof

These considerations are sensitive to boiler pressure, type of coffee, degree of roast, type of grinder, taste preferences and more. This morning I pulled a 7g single shot (17.1g in the cup) on my tank-fed 2014 L1. Coffee: Volcano Mount Blend; Boiler pressure: 1.2 bar; PI time: 30" (beading but no drops); total time: 58"; EY 24.6%. Very pleasant taste in a 5oz cup topped-up with microfoam. I'll probably find this formula tastes over-extracted as black expresso; if so, I will coarsen the grind to increase the flow rate (and consequently shorten the PI), which will lower the TDS and, therefore, the extraction yield.

Of course, all of this, including PI time, would be very different with a different coffee. There are rules for making espresso, but I find that they rarely, if ever, relate to a single variable.


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## dsc

Thanks for the replies. I typically pull 1:3 ratios, used to do 5s PI but I'm now switching to 15-20s as it increases complexity and adds a lot of fruity vibes into the shot. Majority of what I drink hits 21-22% but it's on a conical, so rather high and it used to taste meh, but with longer PI the taste profile is much improved.

With such long PI does anyone know what makes the fruit pop so much? I've got a few ideas but I'm yet to measure group temps during PI to confirm.

T.


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