Breakdown the cooling flush for me?

#1: Post by **brooksie967** » November 19th, 2015, 8:15 pm

Yes, this topic has been beat to death. I've been reading about it, watching videos etc. I'm new

From what I understand, once water is flowing nicely/hissing stops we are somewhere around 205 degrees. There is then a 1 degree drop in temp per second.

I also understand that we should be extracting somewhere around the 200 degree mark.

I don't understand why everyone talks about the 30 to 45 second re-heating process. What's the purpose of this? Seems to me that I want to pregrind/tamp my pucks and brew my shot immediately after my cooling flush?

Someone talk me through this?

Much thanks!~

#2: Post by HB » November 19th, 2015, 8:32 pm

See Flush and go vs. Flush and wait. In my experience, Dragon types like the Elektra Semiautomatica require flush-n-go. Mixers need time to restabilize and thus require flush-n-wait. Your QuickMill Andreja Premium is a Mixer.

November 19th, 2015, 9:53 pm

Thanks for the link Dan,

Still not sure how it works or why the wait is needed though

#4: Post by HB » November 20th, 2015, 12:26 pm

The previous explanation seems fairly clear:

HB wrote:Mixer - key characteristics are modest flush, medium to slow recovery, considerable thermal memory, and initial rising then falling brew profile. Unlike the Dragon, the Mixer's brew temperature isn't determined solely by the output of the heat exchanger. Other factors, such as cool water mixing via an heat exchanger injector, backflow from a thermosyphon, and the attenuating effect of a heavy grouphead temper the final brew temperature. Examples include HX E61 espresso machines like the Vibiemme Domobar Super and Quickmill Vetrano.

OK, that's a lot of terminology. The simple answer is a heat exchanger mixes hot and cold water; how long it takes for the water in the HX to stabilize around brew temperature depends on the particulars of the group's design.