Measuring grouphead temperature

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Mark_Israel
Posts: 12
Joined: 13 years ago

#1: Post by Mark_Israel »

I have an NS Oscar. I'm interested in getting the right, consistent brewing temp for a particular coffee: in this case Counter Culture La Forza. I have a Fluke thermocouple rigged to measure temperature in the portafilter (threaded in through the spout and held down with balled up aluminum foil, as suggested elsewhere in these forums). Counter Culture suggests that 200 degrees is the ideal temp for La Forza. BUT is that 200 degrees in the basket? or should I expect the basket temp to be substantially lower (If so, how much lower) than the water temp as it exits the shower screen?

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HB
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#2: Post by HB »

First of all, keep in mind that Counter Culture's recommended brew parameters are based on a double boiler espresso machine (La Marzocco Strada), not an HX like yours. In my understanding of La Marzocco-speak, 200°F equates to "medium temperature", 198°F = low, 201°F= medium high, and +203°F = high. I don't have hands-on experience with the Nuova Simonelli Oscar, but I believe it's a Dragon HX design. If so, then medium translates to 4-6 seconds after flashing boiling stops with a 6-10 second rebound.

If you want to confirm this ballpark starting point, read Seeking low tech way to measure brew temperature. Snaking a thermocouple up the portafilter spout is reasonably accurate, as is measuring with a fast-acting thermometer + a Styrofoam cup. That's what I did for a long while before the Scace thermofilter arrived on the scene. The low-tech ways are tedious, but work.

That said, I suggest you not spend too much time with thermocouples, thermometers, and foam cups. Instead, I recommend developing your ability to diagnose via taste. It's not hard, especially if you intentionally choose wide variations. For example, if you flush for time X and rebound time Y one time, then flush 2X and Y the second time, you should taste a distinct change in flavor profile (presumably sour-ish and/or flat). Based on your assessment, halve the difference up/down.

If you haven't done so already, review How I Stopped Worrying and Learned to Love HXs, especially the second entitled "What is the 'right' boiler pressure setting?"
Dan Kehn