Is pre-infusion obsolete with lower pressure, spraying of the puck and a bplus screen filter? - Page 2

Beginner and pro baristas share tips and tricks.
mathof

#11: Post by mathof »

Auctor wrote:Which of the Kafatek Flat burrs are unimodal?
I upgraded my Flat from the original Mythos burrs to the Shuriken LM. Kafatek doesn't publish particle size distribution graphs, but there seems little doubt in usage that these burrs are more like EK43s than bimodals.

Auctor
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#12: Post by Auctor »

You could be right. I wanted to confirm whether your comment was based on an analysis, or if it was speculative. There was some recent discussion on the Kafatek forums about this subject.

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longpvo

#13: Post by longpvo »

I also use the bplus lower contact screen with my Breville, it helps 200% on shower head cleanliness and noticeably better water distribution. With the screen I really needed to pay attention to my temperature offset vs no screen, I was trying to dial in a light floral roast today at 92°C (puck prep, dose yield were all good), and it was just a touch overly sour, tried it again without the screen and voila.

Rustic39

#14: Post by Rustic39 »

I'm clearly out of previous poster's league on this thread, as I'm only a bit over a year into my serious home espresso journey. Also, my only experience has been with my old Elektra lever machine, which is kinda apples to oranges concerning the Op's pointed question. Nevertheless, something I've learned with my set up might be relevant to this discussion....I've almost completely stopped rigidly timing my preinfusions, in leu of waiting/watching the naked portafilter for even drop developments across the bottom before releasing. This technique has all but eliminated sink shots entirely for me. Of course the timing varies with roast/grind/dose, but I don't really have to concern myself much by that point after dialing in from shot to shot when I'm simply aiming for a good drinkable shot. On the other hand though, when dialing in new beans this technique self adjusts to the changes I make in grind/dose/age/humidity etc, to give me a good shot or tell me what I need to adjust to get there. I can use this preinfusion technique to help me dial in by gaining information from how long I have to wait on the preinfusion. Things like tamp pressure, grind and dose all provide good feedback via the preinfusion wait time. For example, I may seek a preinfusion duration of 10 seconds but my first grind gets me only 5 seconds till launch time. I can then maybe grind a tad finer, or tamp a tad firmer, and check the next preinfusion time for results. I've found some roasts tasted best at longer preinfusions or shorter ones, but have always had a decent shot when relying on visual indicators vise blind timing. I suspect this is because using this technique may overcome errors done elsewhere, like tamping wrong pressure or grind off some.

Once when I was distracted, I forgot to tamp the grinds in the portafilter. Upon starting my preinfusion step, instead of a wait for the beads of espresso to start forming typically @10 seconds in, I was immediately presented with a fully involved flow. I simply released the lever at that instant, riding the spring loaded lever to the top, completing the shot. Figured it was surely gonna be a sink shot. Turned out to be surprisingly drinkable!

If I were stuck drinking the same beans all the time, I suppose at some point I'd have to play around with this step more, in order to expand the flavor profile of a given bean, to not get board by the same thing always. Instead though, I'm experimenting primarily with home roasting SO beans, roast levels, etc. Enough going on there to keep me with an endless variety of flavors.

BaristaBob

#15: Post by BaristaBob »

Katran wrote: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?

thanks,--
Well, you certainly can't argue with results. When it tastes good...stick with it. Recently I've been experimenting with the bplus/Flair screen and have observed a few things. First, I rotate through many coffees, but currently I'm drinking three that are med-light to medium in roast level. Therefore I use a fair amount of preinfusion...15 seconds worth. I have a "Slayer" modded Breville 920, so I modulate the flow to get first drops at the 15 sec. mark. After that it's the full 9 bars to the end of the shot. A few people have posted that the bplus/Flair screen slows down the flow significantly, but this has not been my experience. I get the same total shot time and yield with or without the screen (same grind). I'm beginning to think the screen has more impact on flow when there is little to no preinfusion (as in your case).

If I can discern any taste difference it might be that my shots without the screen are a little brighter, but I haven't measured the TDS. Both shots are great, there is just a subtle difference. Anyway, for me I use the screen because I want to tone down the acidity just a bit and accentuate the chocolate note of my coffees. Plus the screen really does keep my dispersion shower screen sparkling clean, and makes my puck knock out of the pf like no tomorrow! If there is a area I haven't explored yet with the screen it would be extraction temperature. I believe bplus says that elevating the group temperature by 2-3 degrees is necessary because the screen acts like a giant heat-sink.

Cheers,
Bob
Bob "hello darkness my old friend..I've come to drink you once again"