Is pre-infusion obsolete with lower pressure, spraying of the puck and a bplus screen filter?

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by Katran »

I'm using a Linea Mini, and I modified it for lower flow and lower pressure (pushing about 7.5 bars). I spray my puck with a bit of water to distribute first drops of water a little better. (as seen in the decent espresso video). I also use a bplus filter.

Here's the interesting part: I'm getting better results without pre-infusion (vs infusion of 2 seconds on, 2 off). For the same grind, the TDI's are about the same. The taste is much improved.

What are your experiences with pre-infusion in the lower pressure context?



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Team HB

#2: Post by Jeff »


At least for medium-light and lighter, SO roasts, preinfusion is still, at least for me, an essential.

There's a lot of debate over "line-pressure" vs. just no additional flow. Some believe that line-pressure tends to accent the chocolate flavors and that no-flow brings out more of the delicate flavors. I have some opinions, but far from being able to say anything definitive. (I regularly use a BPlus these days, but found the differences I suspect even before I had one.)

The bottom line is do what works for your water, coffees, grinder, machine, and tastes.

I've been surprised multiple times by "blown" shots that were far from my intent for one reason or another. Taste before sink! (No magic, most do end up in the sink.)

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BaristaBoy E61

#3: Post by BaristaBoy E61 »

Jeff wrote:I've been surprised multiple times by "blown" shots that were far from my intent for one reason or another. Taste before sink! (No magic, most do end up in the sink.)
Humans due unintended an unexpected things; they make mistakes that have led to great discoveries and revelations in all human endeavours - espresso too!
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

Katran (original poster)

#4: Post by Katran (original poster) »

I've started doing small experiments every morning. I'm having more success with no preinfusion, but I have a feeling that it depends on how long the preinfusion lasts. If the preinfusion doesn't saturate the entire puck, doesn't that generate uneven extraction? Wouldn't the wet part extract differently than the dry part? My Linea Mini looks good and can do amazing espresso, but it's no Decent, and there's little feedback and little control on these things.

Anyway, more experiments coming.

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#5: Post by Jeff »

Lots of hypotheses, theories, guesses, and even wrong beliefs about what happens during espresso making, like anything that you can't see (and a lot of things that you can).

As a guess, the more quickly you can evenly wet the grinds (including top-to-bottom), it would seem as though the more evenly the puck would extract, all other things equal. With commercial-level roasts (at least, as I assume that was what the experimentation used), the grind coarse, extract fast approach of Hendon, et. al., seems to suggest that a slow infusion isn't needed. The "need" to grind fine with lighter roasts and use soak to soften the puck seems to be a force that opposes that. Who knows?

Katran (original poster)

#6: Post by Katran (original poster) »

Yes, I agree, I don't have much data.

I've been doing more medium-dark roast lately, and the difference in extraction that you mentioned is noted. I'll just continue experimenting...

For ristretto with a medium-dark roast, the non-preinfusion is definitely better to my taste buds, also higher TDS for the same grind size.


#7: Post by Eiern »

I find that I want to use a slightly slower saturation of the puck (I then use 3,5 ml/sec instead of my full 6 bar until it drips and gently open up the flow paddle) for some of the beans I want a little less acidity from. I pull mostly Wendelboe and similar filter roasts, and pretty fast flow. I use Flair screen. If I had anything darker roasted I'd probably skip the gentler start for every shot with my setup.

I think this is bean and grinder dependent. I also grind a little finer with the slower start but end up with similar pressures and flow only delayed a little. Doesn't measure very differently but it changes the balance of the shot a little.

I find I get a little more clarity of flavor and more acidity with flat fast flow and a little more body and bass notes (just call it chocolate) with slower start. I think the slow start might work better in milk.

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#8: Post by TigerStripes »

I regularly do 10-20 second pre infusions with med-light roasts - I wouldn't really consider 2 seconds pre infusion. It's more like a gentler ramp up to pressure at that point. There's a lot of room to play with pre infusion to adjust flavors and 2 seconds is barely scratching the surface.

I love long preinfusion with my Kenyan sl28 so I vote no - not obsolete :mrgreen:
LMWDP #715


#9: Post by mathof replying to TigerStripes »

These matters are grinder dependent. The unimodal burrs on my Kafatek Flat work best with short infusions. I think the reason is that the relative absence of fines allow the puck to quickly fill up with brew water, even when it's ground very finely.

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#10: Post by Auctor »

Which of the Kafatek Flat burrs are unimodal?