Looking for a Simple Measure of Preinfusion - Page 2

Beginner and pro baristas share tips and tricks.
Tonefish

#11: Post by Tonefish »

Great thoughts here. I appreciate the n-grams approach since there are so many ways to preinfuse, and I also believe that the preinfusion ends when some level of pressure is reached and the pump stays on. I think of it as a combination of pump full-on and drops entering the cup as I don't preinfuse any longer once I see drops, but maybe that is more complicated than useful (I tend to do that). Is there not room for a qualifier, if it makers sense, that once you drip into the cup at all, the preinfusion should be over and the pump engaged on a path to maximum pressure for the intended profile?

One thing I resonate with too is this:
AssafL wrote:If you don't let the PI continue to the end, the wet part of the puck (the top part of the puck), will act as a piston on the bottom part of the puck - the dry part. Being dry, the air (being compressible) will be pushed out and density will increase. Either the puck will be sealed, or water will be forced to find channels or, if the layer is thin enough, continue PI SLOWLY. Obviously SLOWLY depends on the size of the grinds. Boulders will be easier for the crushing water to permeate.
I repeated the Jim Schulman-Ken Fox preinfusion experiments and got the same results of a shallow cone of dry coffee, of diameter about 50-60ish percent of the basket diameter and a height of 25-40% of the coffee height. The thing that amused me though, is that the once I hit the pump after preinfusion, the extraction begins is earnest from the cone botttom, as though the dry puck offered temporarily less resistance than the wetted part. This kind of makes sense though since preinfusion typically offers a finer grind for a given dose and coffee.
LMWDP #581 .......... May your roasts, grinds, and pulls be the best!

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another_jim
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#12: Post by another_jim »

JayBeck wrote:As I understand it, the Decent Espresso DE1 defines the end of preinfusion as pressure rises. ...
If the idea is a machine independent measure, the only indicators are time, shot weight and visual flow. At least, I think so.

On the Bianca, I've gotten very attached to using the group gauge to keep the P/I at 2.5 - 3 bar; but I can make lever shots with identical P/I just by lifting the lever a bit and holding it (or timing the pump filling the group up on the Strega).
AssafL wrote:Conversely, if it is still drip-drip at 5gr, you are really no longer espresso....
The only reason I nominated 5 grams is that I've been experimenting with very long, 30 second and more, P/Is, as have others. In terms of taste and texture, I'm not sure it's espresso either. It's doing steeped coffee on an espresso machine. However, I think this may become a thing. In that case, you won't be dividing between puck wetting time and flow, but between steeping time and flow.

In terms of procedure, puck wetting time ends when there is the first sign of coffee at the bottom of the basket in a naked PF; steeping times ends when you go from dripping to flow. The first will, by definition be shorter than the second; and they represent two separate events.

If you are into espresso porn, you don't want any dripping. You want the coffee to collect at the bottom of the basket and flow vigorously. But the recipe for that is coarse grind, overfilled baskets, and underextracted shots. If you are into finer grinds and higher extractions, there's a lot more dripping. If you want both high extractions and espresso porn shots, you have begun on an endless quest for magic baskets and grinders.
Jim Schulman

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CarefreeBuzzBuzz
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#13: Post by CarefreeBuzzBuzz »

Jim,

On a given machine aren't there other factors that would go into hitting the 5 grams even with the same coffee. I'm not the engineer type so I throw these out there.

On my Slayer:

water temp,
brew pump pressure,
flow rate,
basket type,
ambient conditions of altitude and possibly others

There may be others but these all come to mind as to how long it will take until I get five grams which I sometimes will try to see if I like the results more than going to full pressure after the first drops are seen or the first drops in the cups.

Michael
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Peppersass
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#14: Post by Peppersass »

another_jim wrote:...I've been experimenting with very long, 30 second and more, P/Is, as have others. In terms of taste and texture, I'm not sure it's espresso either. It's doing steeped coffee on an espresso machine. However, I think this may become a thing...

If you are into espresso porn, you don't want any dripping. You want the coffee to collect at the bottom of the basket and flow vigorously. But the recipe for that is coarse grind, overfilled baskets, and underextracted shots. If you are into finer grinds and higher extractions, there's a lot more dripping. If you want both high extractions and espresso porn shots, you have begun on an endless quest for magic baskets and grinders.
One of your best posts, Jim, and that covers a lot of posts.

I completely agree that it's questionable to call these light-roasted, large-brew-burr ground, profiled drinks we're making espresso. They can be very tasty, but they're something else. "A thing", as you say.

And I might add that making true espresso doesn't mean you have to sacrifice subtle origin flavors, and you'll get better mouthfeel. You just have to use coffee that's properly developed (and not ultra-light), rest as needed, grind and pull with quality gear, and use solid technique. You may even be able to get good results from lighter roasts simply by pulling Lungo, albeit with less mouthfeel.

But that's just my opinion.

Tonefish

#15: Post by Tonefish »

another_jim wrote:In terms of procedure, puck wetting time ends when there is the first sign of coffee at the bottom of the basket in a naked PF; steeping times ends when you go from dripping to flow.
Agreed, and I believe preinfusion should end with the first sign of coffee seen when viewing the bottom of the basket with a blind portafilter, but I'd assume the "Simple Measure" would need to accommodate those w/o a bottomless portafilter. The first thing they would see is drops in the cup.

Also, whether you wet, bloom, or steep, isn't that all included under your definition of preinfusion? At some point, pushing hot water with pressure through coffee is required to have espresso, so if that isn't happening, it is not espresso. The preconditioning of the coffee has been a part of espresso since at least the E61, so there must be some room for variety of preconditioning and the result still considered espresso. Maybe the first step is defining what is included in the scope of "preinfusion."
LMWDP #581 .......... May your roasts, grinds, and pulls be the best!

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RapidCoffee
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#16: Post by RapidCoffee »

The DE1 allows an unprecedented degree of insight into the extraction process. Here is an extraction inspired by Dan's 4-9-6 pressure profile in the Bianca review: preinfuse at 4ml/s to 4bar, briefly increase pressure to 9bar, then gradually decline to 6bar until target weight (32g) is reached.
Image
Preinfusion ends at 14s

During the preinfusion phase, water flows into the puck at 4ml/s (blue curve). Pressure (green curve) remains very low until the puck is saturated. As grinds wet and swell, flow reduces and pressure increases to 9bar. Not coincidentally, this is precisely when the first drops appear on the bottom of the basket (14s).

In light of this, the best measure of preinfusion is a fully saturated puck. On most machines, this is easiest to determine when the first drops appear on the bottom of the basket.

<gripe>"Preinfusion" is lousy nomenclature! Better names for wetting the puck would be "infusion" or "saturation".</gripe>
John

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AssafL

#17: Post by AssafL »

RapidCoffee wrote:The DE1 allows an unprecedented degree of insight into the extraction process. Here is an extraction inspired by Dan's 4-9-6 pressure profile in the Bianca review: preinfuse at 4ml/s to 4bar, briefly increase pressure to 9bar, then gradually decline to 6bar until target weight (32g) is reached.
<image>
Preinfusion ends at 14s

During the preinfusion phase, water flows into the puck at 4ml/s (blue curve). Pressure (green curve) remains very low until the puck is saturated. As grinds wet and swell, flow reduces and pressure increases to 9bar. Not coincidentally, this is precisely when the first drops appear on the bottom of the basket (14s).

In light of this, the best measure of preinfusion is a fully saturated puck. On most machines, this is easiest to determine when the first drops appear on the bottom of the basket.

<gripe>"Preinfusion" is lousy nomenclature! Better names for wetting the puck would be "infusion" or "saturation".</gripe>
I think Jim is looking for standard way of describing the recipe. With extra long PI and with Scott Rao's paused pulls. It is harder to define when PI is over with those (or blooming or whatever they may be called).

Something I don't understand: during PI flow is 4ml/sec which goes on for 14 sec making it 56ml that were drunk up by the puck during PI? How much was the dose (for a 56ml PI I'd expect perhaps 30-40gram dose). Am I missing something?
Scraping away (slowly) at the tyranny of biases and dogma.

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Jake_G
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#18: Post by Jake_G » replying to AssafL »

DE1 machines have 4mm more headspace than most. 4mm by ~58mm gets you an extra 10.5ml in there, but there's still something funky going on here...

That said, my 4ml/sec shots also take around 14s to bleed through, but my flow decays as soon as the puck starts generating back pressure so I'm left confused.

Is the goal of this discussion to be able to describe any type of preinfusion by saying "it took x number of seconds to get y number of grams in the cup" and have that somehow be a universally meaningful descriptor, regardless of the method of preinfusion? I'm with John, in that the nomenclature is not helpful, given what's going on. If "infusion" means stuff is coming out of the basket, then "preinfusion" is anything before that happens. Not sure what the answer is, but I'm interested!

Cheers!

- Jake

Bunkmil

#19: Post by Bunkmil »

I own a DE1 machine and I have similar results using 18g of coffee in a VST 18g basket. It might have to do with the grouphead design of the DE1 having more headspace on the top of the puck than most machines. I always get 15ish seconds of PI at 4ml/s but I personnaly prefer a lower flowrate PI (around 2ml/s) for the type of coffee that I'm drinking (plus a declining temperature profile but that's another discussion).

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RapidCoffee
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#20: Post by RapidCoffee »

AssafL wrote:Something I don't understand: during PI flow is 4ml/sec which goes on for 14 sec making it 56ml that were drunk up by the puck during PI? How much was the dose (for a 56ml PI I'd expect perhaps 30-40gram dose). Am I missing something?
An 18g dose could soak up 36ml, plus headspace (and non-instantaneous onset of flow)... gets you in the ballpark. When I increase flow rate to 8ml/s, "preinfusion" time is cut in half (14s to 7s). So it's fairly consistent.

The point is, something interesting happens at 14s in the graph: flow plummets and pressure rises. This is also when first drops appear on the bottom of the basket. If you prefer to define preinfusion as something that happens 4-5 seconds later, when this flow/pressure transition is complete, then perhaps "5 grams in the cup" makes more sense.
John