Posted Fri May 20, 2005, 6:40am Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
andys Said:
Hi Bob!
Do you have graphs that focus on the actual shot pulls? With perhaps, a one or two second interval on the X axis?
I understand the point you're making, but that graph just indicates that the temp are fairly consistent. There isn't enough detailed information to make the earth-shaking conclusions that we strive to make on Coffeegeek. :-)
I'm all for more data. Sometimes though I wonder if that misses the point. Bob has publicly said the most important aspect -- taste -- is consistent shot-to-shot. He's a good cupper, better than I'll ever be. So tell me again why we need a chart?
-- Dan
True confession: Like I should talk! A couple times I've focused so intently on the process, I forgot to taste the espresso before it was cold. That's when I banned the TCs and its ilk from the countertop. They're still in the drawer and I feel better for it.
Posted Fri May 20, 2005, 6:42am Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
andys Said:
Hi Bob! Do you have graphs that focus on the actual shot pulls? With perhaps, a one or two second interval on the X axis? I understand the point you're making, but that graph just indicates that the temp are fairly consistent. There isn't enough detailed information to make the earth-shaking conclusions that we strive to make on Coffeegeek. :-)
But of course; anything for you, Andy (and the shattered, coffee-soaked earth).
I know you are not into details [just kidding], but nevertheless, here a few to better understand my goals. The "shots" are 2 oz. of water into a dense sponge in the PF where the coffee puck usually sits, and the TC junction is just below the top surface of the sponge facing the group. My purpose in doing this exercise was to confirm my belief that I am getting fairly good temperature consistency shot after shot, with my current regimen. The target temperature of 200 deg F +/- 1 deg is determined by what tastes good to me with coffee in PF using this exact routine and may or may not be 200 deg F with coffee in the puck, although I suspect it's fairly close. In any case, it's the sweet spot temperature for my palate for a wide variety of bean types and roast levels when I test it with a sponge in the PF. I can vary the 200 deg F. target temp accurately, by tiny changes in the routine to better match some coffees, but that's another story.
Also, I know that it takes from 5 to 7 sec, to pump 2 ounces of water through the wet sponge in the PF with this configuration, so the "pulled shots" are actually roughly 8-sec, 2-oz. "shots" of water being pumped through a dense sponge. The 8 sec. includes pushing the lever up and afterwards down. Again, I was looking for consistency and not an absolute simulation (if that's even possible) of a coffee-filled PF. So without getting into the whole issue of what exactly happens to water when it goes through a coffee-filled puck, fines, gradients, etc., etc., this, for me, is a reasonable, indirect method of verifying what my palate suspected.
This chart happens to be the third "shot pull" in the series posted above, but they're all quite similar. I sampled every second.
Posted Fri May 20, 2005, 5:17pm Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
boby Said:
My purpose in doing this exercise was to confirm my belief that I am getting fairly good temperature consistency shot after shot, with my current regimen.
I wasn't trying to bust your chops and I wasn't trying to split hairs about temperature variation. The point I was trying to make is that, at this point in time, no one really knows how important precise temperature control is.
It may be very important with some blends, less so with others. It may be very important to some people because their personal tasting apparatus is more sensitive to a particular aspect of flavor than others. It may be very important if your temperature profile is extremely flat between second 6 and second 26 of the shot, and unimportant if your machine delivers a humped profile....etc, etc, etc.
Seems to me, all bets are off until the subject has been studied very thoroughly with equipment that probably doesn't even exist yet. I know you made the statement that your taste buds are only "calibrated" within 1 degree -- but, with the right equipment, with certain blends, and perhaps with specific temp profiles, who knows?
Meanwhile, I fully understand if you say that the Andreja is "good enough," and simply forget the measuring and get on with the coffee. :-)
Remember me? I started this thread, and it seems like 20 years ago :). So, what I'm going to say next is just a comment on measuring brew temp, and it should be totally divorced from the final result which is all I care about YOU LIKE THE COFFEE IT PRODUCES. End of discussion right there.
I spent way too much time studying brew temp on H/X machine and duel boiler machines using real coffee, and a modified P/F that can simulate a real shot by regulating flow rate in the P/F. Dense sponge is a lousy compound to simulate coffee. Why?
Particularly on a H/X machine, but according to my measurements also on duel boiler, the speed of water flow in the P/F regulates brew temperature. It is amplified on a H/X machine because it also regulates the speed in which water exits the H/X. On a duel boiler, the variation will be more subdued, and has more to do with "sitting water" in the P/F. Having 2 oz run in 8 seconds instead of 25 changes your actual brew temperature average by a very large margin.
My argument here is not that if you were to test it with real coffee you would have a very large variation of temp within the shot. It will be 1-1.2 f from the 6th second on. What I'm saying is that you are unable to measure your real average brew temperature by using the sponge method. (Average Brew temperature from the 6th second on). But don't let this spoil your coffee, it is your taste buds that count, and not all the technicality around it :)
Reasnor Senior Member Joined: 3 Apr 2002 Posts: 66 Location: Waterloo, IA Expertise: I live coffee
Espresso: Nuova Simonelli Appia Grinder: Mazzer Super Jolly, Baratza... Vac Pot: Yama Drip: Technivorm Roaster: Popcorn Popper, SC/GG
Posted Tue Jun 7, 2005, 10:24pm Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine - A Workable Soluti
I'm excited to try the volume-specific flush and timed rest period tomorrow morning (12:30am right now). One question I have, however, is if anyone has run experiments using the Nuova Simonelli Oscar? I haven't seen this machine under people's profiles, and am just looking for some more pointed information (if it exists). Thanks in advance,
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