What is the standard for reporting brew temperatures?

[MOSFET]

Maybe this should be common knowledge by now but when everyone gives a temperature for a blend, is there a standard? Is it the peak temperature of a thermocouple embedded in the grounds in the portafilter or is it the temperature of the water just before it hits the coffee? For example, under the screen or in the banjo bolt (of a LM). These are definitely two different temperatures. I'm sort of saying this rhetorically because even if it's a standard like in the center of the puck, then there could still easily be 1-2 degrees F variation among users' thermocouple-meter setups. Still, I'd like to hear what people are using when they report temperatures for blends.

thanks

Keith

[HB]

Really good question! Different espresso machines, especially HXs, have different temperature profiles, but I report the brew temperature measured with a thermofilter mid-shot. As shown in the chart below, where you measure makes a huge difference:

Monitoring Brew Temperature - E61 & Silvia: Four different repeatable measurement points. Which offers "better" information?

This is a composite of various measurements I've posted over the last couple years, representing the typical output of the thermofilter (red), over-the-basket-lip (yellow), your TC adapter (blue), and just for fun, the bottom of the basket (green). Being closer to the point of delivery at a standard position like the thermofilter is better if you want to compare brew temperatures among machines, but an equally interesting question is this: How can one squeak more performance using sensible temperature management from "old school" machines (for those who can't afford GS3's)?