Ian Moderator Joined: 21 Jan 2003 Posts: 1,402 Location: England
Espresso: Euro2000,Rancilio Grinder: Mazzer,La Cimbali Vac Pot: Cona-->CraigA Drip: Belgique for emergencies Roaster: Primas with variac
Posted Sat Dec 4, 2004, 4:08am Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
Hey Abe, that's an interesting chart, thanks for posting it. I'd like to duplicate your experiment but wouldn't be allowed the 14 hours spare time required ;-)
Whew! That's A Lot of Blah Blah (place smile here)
Abe_Carmeli Said:
The problem with Dan’s method is that on my machine, watching the water flow to determine water brew temperature still leaves a margin of error of 4-5 degrees. That margin of error can bring me to a brewing temp that is either too low or too high. I was looking for a method that will consistently produce 202-203 degrees brew temperature.
Posted Sat Dec 4, 2004, 8:58am Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
This may be useful for Andreja owners...
Ok - I stayed up late and got up early cause this thing had got me going! But I'm a real happy camper now and Abe, thanks for pointing the way. I can now pull shots, one after the other at any common brew temperature of my choice, by measuring the flush water quantity and watching a stop watch! My method is slightly different than Abe's.
My water quantities and times are a bit different from Abe's due to the difference in machines (not so much due to the water in the tank although I saw that that did make a small difference). First, just to give a reference, my pstat is set at a max. of 1.05 bar, not the 1.2 it was set at when I got it. After many, many data-logged measurements here's the bottom line and remember, this fits my routine and my machine (I take a leisurely 3 minutes to flush, grind, fill, tamp, lock and load and place the cup). I ain't no pro with customers lined up and I ain't in no hurry!:
If the machine has been idle for a while, flush 6 oz.
After three minutes, flush 2 oz.
Wait 40 seconds and pull the shot.
That's it! I pulled 40 shots in a row using this routine (2. and 3.) and the shot temperature was 203 plus/minus 0.5 deg F for every one!!! If I want a 202 deg F shot, I wait 30 sec. and for a 201 deg F shot, 25 sec. I'll probably make a time chart for the Andreja, in case I want to go above 203 or below 201 deg F for brewing temps.
Some additional info: Every one of the 2oz flushes before pulling the shot (after waiting 3-minutes since the last shot) were also stunning in their consistency, peaking to 205deg F and hitting a minimum 194 deg F plus/minus 0.5 deg flush after flush. I was amazed! This means that I can hit any temperature I wish between 194F and 205F by simply changing the length of time for the 2oz. flush.
The difference between my method and Abe's is that his is designed to provide a 202-203F shot every time. I've standardized on a 2oz flush and just change the timing for different temperatures. For me, it's easy to remember 2oz, 40-sec-wait for 203, 30-sec-wait for 202, 25-sec-wait for 201.
Yes, I'm a happy camper and thanks Abe and Dan for providing the foundation. Of course none of this is earth-shattering; Jim S. has been saying this for eons and many other HX, E-61 owners have routines similar to this. It's just that I've never seen it documented this way before and never for the Andreja, specifically.
BTW, Dan, if you're listening, could you try this on your Andreja if you still have it and comment (and if you have time)?
No, all the test machines went to the CCC EspressoFest (see highlights). Those that didn't sell at the show are still at Counter Culture Coffee or will soon be shipped back to event sponsors. Although I didn't systematically measure volumes as you and Abe have, your succinct rules sound consistent with my experience.
Posted Sat Dec 4, 2004, 11:48am Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
Bob,
Congrats, that method must be a winner for the Andreja. It is simpler than my routine on the Giotto. I tried it briefly on the Giotto but due to the differences in the machines and brew pressure it does not work. I will try to adjust the flush times and quantities for the Giotto, using your simple rule and see if it fits.
In the meantime, I did some more tests this morning. I wanted to try the chart on a machine that has been warming up for not more than 25 minutes and see if there is a difference. Simulating first shot of the day for some people. I did find that the flush quantity for the first flush needs to be adjusted as well as the recovery time. Did you try your routine under those conditions?
x Senior Member Joined: 29 Sep 2002 Posts: 322 Location: x Expertise: I love coffee
Posted Sat Dec 4, 2004, 12:24pm Subject: Re: Fine Tuning Brew Temp. on a Heat Exchanger Machine - A Workable Solution
Hello Abe,
Thanks for all the work and sharing.
For folks that don't have a TC setup, if a person were using the
"listen to the water coming out of the portafilter to wait for it to stop flashing to steam or gurgling"
method of temp. control that Dan has outlined do you think your tests would correlate to, or validate this simpler method. I realize one would better off with some hard numbers to reference from, after the hard numbers a person would have 2 handy tools to work with, sound of water and volume of water during cooling flushes.
Example: With a 5 min. idle and a 6.5 to 7 ounce flush at what point would the water exiting the portafilter stop sputtering? If both methods are reasonably accurate one would assume maybe 3? ounces and then count seconds to arrive at desired temp of 202 equaling the 6.5 to 7 oz. total flush.
I didn't state this as succintly as I probably could have, I am starting to think I need to take a class on Technical Writing to post here anymore as topics become more a bit more complex, hope it comes across making sense. Thanks again Loring
Posted Sat Dec 4, 2004, 1:06pm Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
Abe_Carmeli Said:
Bob,
Congrats, that method must be a winner for the Andreja. It is simpler than my routine on the Giotto. I tried it briefly on the Giotto but due to the differences in the machines and brew pressure it does not work. I will try to adjust the flush times and quantities for the Giotto, using your simple rule and see if it fits.
In the meantime, I did some more tests this morning. I wanted to try the chart on a machine that has been warming up for not more than 25 minutes and see of there is a difference. Simulating first shot of the day for some people. I did find that the flush quantity for the first flush needs to be adjusted as well as the recovery time. Did you try your routine under those conditions?
No, not yet. I usually give my machine at least an hour to stabilize and in the case of many of my measurements, early this morning, the machine had been on continuosly for nearly 24 hours. But I will try it over the next few days and report back.
Posted Sat Dec 4, 2004, 1:41pm Subject: Re: Fine Tuning Brew Temp. on a Heat Exchanger Machine - A Workable Solution
x Said:
Hello Abe, with a 5 min. idle and a 6.5 to 7 ounce flush at what point would the water exiting the portafilter stop sputtering? If both methods are reasonably accurate one would assume maybe 3? ounces and then count seconds to arrive at desired temp of 202 equaling the 6.5 to 7 oz. total flush.
That point is machine dependant. On the Giotto, it is around the 70 % flush quantity. However, I found it hard to judge by watching the flow alone.
It is my experience that at that noticeable point, where it stops visible sputtering, the temperature is still too high, it is around 210 f. on the Giotto. To bring it down to 201-202 degrees, you should let it run for about 40% of what it has already run. That is if you have 3 oz flushed at that point, have it flush 1.2 oz more. If you want to count seconds from that point, check on your machine how long it take it to release 1 ounce of water during a pull and use it as your measurement. If it takes it 3 seconds to release 1 ounce, in the above example you need to count about 4 seconds and stop the flush. Then count 30-35 seconds and pull your shot.
Dan Kehn is a much better judge of water flow than I am. Dan, if you are still there, what is your take on this?
Posted Sat Dec 4, 2004, 1:51pm Subject: Re: Fine Tuning Brew Temperature on a Heat Exchanger Machine
I’ve added some more data to the flush chart. There is a section dealing with machines that were warmed up to a minimum of 25 minutes to simulate first shot of the day for some people, and the affect of using a bottomless portafilter. I also integrated the flush routine into the grind, dose and tamp routine.
Man, I must stop doing this and get out of the house. See attached.
The sound is telling, more so than the "sputtering" you'll see. Nonetheless, in the video that accompanied my article, the visual transition is very distinct -- right between the 24 and 25 second mark. For that particular machine, the temperature is 206F at that point.
I intentionally showed a cooling flush after the machine was idle for a long time to make the point very obvious -- you can see the water practically splashing across the driptray for the first 15-20 seconds. The sputtering during a cooling flush within a few minutes of another would be less vigorous and the transition harder to discern. Even so, if you watch the dispersion screen, you'll see the bubbling and churning, hear the hissing, then finally an abrupt calm. Whether you're using a thermometer, measuring cup, stopwatch, whatever, recognizing that point shouldn't take much practice.
As a test, try watching the video and focusing on the water flow. Ignore the digital display. Press the "pause" button when you notice the sudden calm. After three or four viewings, I bet you'll press pause within 0.5 degrees of 206F. Counting (or measuring, if you prefer) from that point should consistently give the same starting point, except for those who pull shots in rapid succession. As long as the starting temperature is the same shot-to-shot, you can then adjust the "rebound time" to taste as Bob suggests and put aside aids like measuring cups, timers, etc.
In my view, consistency is the name of the game. Most home barista probably don't want to invest the time and money in precise, fast-reaction thermometers / TCs. My advice emphasizes a "no tools required" approach, although I certainly agree that accurate measurements like coffee weight, tamp pressure, temperature, brew pressure, etc. give valuable feedback that can move one along the learning curve faster.
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