Yesterday afternoon I rigged up a simple brew temperature measuring device by drilling a hole in the bottom of a single basket that I never use, and inserting a K-type probe to a level just below the coffee cake. I sealed the probe in with a liquid weld, which took until this morning to set.

Previously, over a long period, proceeding by taste alone, I had settled on a combination of a pressurestat setting (0.85 bar) and a group temperature at the start of the pull (82.5C), measured at the side of the cylinder just above the flange, as a good starting point for most coffees. But I had been wondering whether this corresponded to the brew temperature reported by many users on this forum of between 91C and 94C.

This morning, I was pleasantly surprised to find that these parameter settings do indeed yield a similar result: 93.6C at the start of the pull, 91C at the end. I will have to do a lot more measuring to confirm these results, but I thought I'd report these interim findings in the heat of the moment (so to speak).

For completeness I might add, with the group reading 87.5C at the beginning of the pull, the max heat near the surface of the coffee cake was 98C; and set at 80C, it was 92.6C. It's interesting what a difference a few degrees of difference at the outside surface of the group makes to the temperature of the brew water.

I should also add that I have recently installed a "cooling fin" made by Tije in Amsterdam, and described in this forum a year ago:

La Pavoni cooling fin

I expect this was the reason that the brew temperature dropped during the pull, as it is known that the small mass of the unmodified La Pavoni cylinder does not draw off enough heat to have this effect.