The Relationship Between Water Temperature and Boiler Pressure on a Pre-Millenium La Pavoni - Page 4

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drgary
Team HB

#31: Post by drgary »

I tend to start my lightest roasted coffees at about 207F to 208F on the group, measured on the side where the bell starts to widen. The top end temperature varies depending on how frequently I do the half pumps to get there. My boiler pressure is generally a bit below 0.9 bar.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

ds

#32: Post by ds »

I only have Millennium Pavoni, but something with this does not look right. Specifically where is heat disappearing? If group head is at 224F, the water out of boiler at 0.9 bars is about 240F so group cannot be dropping it down to 202 at all since its already at 224F... So where did heat disappear to get water down to 202F given that group-head is doing the cooling? I suspect some measurements here are not right...

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[creative nickname]

#33: Post by [creative nickname] »

vze26m98 wrote:Anyone have a favorite "light, fruity" espresso blend that pulls well at 203-4? I've assumed that Velton's Bonsai would be in that category, but maybe I'm totally off base.
Mountain Air's Black Balsam Blend would be a good example, and it is one of my favorite new discoveries.
LMWDP #435

vze26m98 (original poster)

#34: Post by vze26m98 (original poster) »

ds wrote:I only have Millennium Pavoni, but something with this does not look right. Specifically where is heat disappearing? If group head is at 224F, the water out of boiler at 0.9 bars is about 240F so group cannot be dropping it down to 202 at all since its already at 224F... So where did heat disappear to get water down to 202F given that group-head is doing the cooling? I suspect some measurements here are not right...
Hi David-

Although I can't imagine where there could be problems with my measurements, I won't insist that they're unassailable. However, I might suggest the following:
  • .The thermocouple inside the basket is inside the puck, not at its top, so the measurement to some extent includes the mass of the coffee.

    . As I'm sure you know, there's a big variation in temperature across the grouphead.

    . If you look at the puck thermocouple line prior to the pull, you'll see it's running a little below 90F. Some bad physics that presumes the temperature masses meet in the middle, ((240-90) / 2) + 90, suggests 165F as the outcome. Given the larger mass of water, is a ~40F higher temperature so surprising?
Thanks for your comment! Charles

vze26m98 (original poster)

#35: Post by vze26m98 (original poster) »

Thanks Gary and Mark for the elucidation of your techniques, and the recommendation of favorite coffees!