Looking for a Simple Measure of Preinfusion - Page 6

Beginner and pro baristas share tips and tricks.
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Postby AssafL » Nov 08, 2018, 3:13 am

Tonefish wrote: I'm struggling with what CBR means? .

Sorry for that. CBR is coffee brew ratio.

CBR = Coffee out / coffee dose.

CBR and timing make the coffee.

EY is a nice control point but not important as a recipe point. Actually TDS - EY is just a rationalization; a complicated way of displaying TDS as a function of dose and bev weight. One could say dose (and thus EY becomes easier to calculate) but dose, given Jake's PI thread, should be a function of basket diameter, headspace, etc. to allow the required PI.
Scraping away (slowly) at the tyranny of biases and dogma.


Postby iggles_and_espresso » Nov 08, 2018, 11:45 am

I like the 5-gram suggestion. As a new Bianca owner, it's hard to even know where to begin experimenting. Being able to test different preinfusion times would be a great place to start, and the 5-gram benchmark enables just that.

But I wonder if this approach is a bit too scientific.

Some pursuits are more like art than science. Take baking and stove-top cooking. Baking is chemistry; it requires the careful combination of materials in just the right way to get the reaction you want. Stove-top cooking is more spontaneous; great cooks make on-the-fly changes using a tool-belt of techniques. Both cooking and baking are, at bottom, science. But artisans in each field approach their craft very differently.

For a long time, making espresso with a non-lever machine was like baking: Get the best raw materials, pop them in a portafilter, and hope for the best. Now, machines like Bianca and the DE1+ let us change our technique from shot-to-shot, almost on the fly. Now we get to be like chefs.

Shouldn't we focus on developing techniques, rather than quantitative benchmarks? For example:

Low-slow preinfusion
High-stall-bloom preinfusion
Ramping preinfusion
Lever style shot
Many others?

Wouldn't it be great to have a language of different techniques, and corresponding knowledge of how those techniques affect the shot. What are the techniques that make great espresso? And how do those techniques apply across different roasts, beans, and temperatures?

*edited to change seconds to grams.


Postby Marcelnl » Nov 08, 2018, 12:00 pm

Believe we were talking about 5 grams, I would not call that weight after amount of time x a quantitative benchmark but a way point that can be used to describe events occurring to later try to correlate them to aspects of flavor and smell etc.
LMWDP #483


Postby iggles_and_espresso » Nov 08, 2018, 12:15 pm

Fair point about grams. I had forgetfully written "seconds." I made an edit to fix that mistake above.

I think my point still stands, though. It might be more productive to talk in terms of techniques to get at those taste and smell correlations, rather than starting with bare physical numbers.


Postby mathof » Nov 08, 2018, 3:09 pm

I have been reading this thread from the perspective of the user of a lever machine and I just don't get the question. For me, preinfusion ends when I release the lever. At that point there is beading visible on the bottom of the basket and, sometimes, a drop or two in the cup; 5-30 seconds will have elapsed, depending on the coffee and grind. By the time there are 5 grams of coffee in the cup, the shot is well underway. What then is the significance of x grams?

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Postby chopinhauer » Nov 08, 2018, 6:21 pm

Ditto, the above post, except that I use a manual lever, a Cremina.

Here I preinfuse at boiler pressure (0.7 bar) for 10 or so seconds, then push down on the lever to about 3 bar for another 10 or so seconds until I see drips. For me this 2 stage process = preinfusion. Once I see the drips I can increase the flow by adding more pressure up to 9 bar depending on the flow rate I'm after. Total shot time from lifting the lever till end of shot is around 50 seconds; preinfusion 20 seconds + flow 30 seconds). This yields a very viscous, mouthfeely, ristretto (15.5 grams in and out; 1:1) with my medium dark roasted beans.
LMWDP #027

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Postby another_jim » Nov 08, 2018, 7:24 pm

mathof wrote:I have been reading this thread from the perspective of the user of a lever machine and I just don't get the question ...

chopinhauer wrote:Ditto, the above post, except that I use a manual lever, a Cremina.

Try doing that with a Turkish grind. You'll be switching the machine off and waiting it to cool to beat the pf sneeze.

Then do a slight pressure on the Cremina, or a lift to about about 7:30 and hold on the spring lever, all for about 30 secoonds, until you see the first drops. Then make your shot as usual. Congrats, you've just made a EK43 shot on your lever.
Jim Schulman


Postby mathof » Nov 09, 2018, 6:33 am

I'm game. I can buy some light roast Scandinavian espresso roasts in London and try to pull a Slayer-style shot with my original-model L1 (PI at boiler pressure) and Monolith Flat (Mythos burrs). Let's see if I've got this straight.

1) grind ~20g ultra-light roast powder-fine
2) use appropriate VST basket
3) preinfuse for ~50 seconds (at what boiler pressure?)
4) lift lever slightly and hold until I see drops (if I don't in ~30 seconds, grind coarser?)
5) release lever


Postby happycat » Nov 09, 2018, 11:41 am

Did someone define the beginning of PI?

I was thinking it differs based on the interface with the espresso maker

For my Gaggia Classic (I added a PI function)
- press start and hear pump start (but don't know when water hits the puck)

For my Flair manual leveer
- after I pour water into cylinder but before add piston?
- after I add the piston and bring lever down to start pressure?
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Graham J

Postby Graham J » Nov 10, 2018, 1:33 pm

There are a massive number of potential variations within the preinfusion phase, from nominal start to nominal end point. Nominal start is when some mechanical means of engaging puck and hot water begins.Nominal end can be when the puck begins shedding more than a few drips into the cup.
Plus or minus 1-2 seconds or 1-2 grams will only matter to the individual. Although I nominated the start of a stream, coalescing from drip, it is not a critical difference from some of the other nominated end points.
An espresso recipe database will produce grouped and normalised and trended data which will be more useful than a lot of the fine detail, which individual barista's or hobbyists can enjoy developing.
Maybe its in line with cooking - most of these recipes have more ingredients, more stages and more potential variation than an espresso shot, but the recipe gives you some sound basis to work from, to individualise and improve your techniques. We don't need to be told exactly how long to use the spatula!