Re: Input Water Temperature on HX Machines

Barry Jarrett <barry@xxxxxxxxxxxxxxxxx> wrote:

| On Sun, 30 Oct 2005 05:29:52 GMT, ross@xxxxxxxxxxxxxxxxxxxxxx (D.
| Ross) wrote:
|
| >Why not? If this is a plumbed machine, and the seasonal water temp
| >difference is large (say 30F), won't the user have to adjust the service
| >boiler temp (and possibly his shot 'rhythm') to compensate?
| >
|
| only if the machine is operating at or near its capacity.

Maybe I'm being dense, but I still don't get it. OK, you step up to your
machine after it has been idle for a while, and bleed off the first N ounces
of water that have been sitting in the HX and are way too hot from the
boiler. The next few ounces - the one for your shot - come from the water
line, pass through the HX in the boiler and are heated in the process by
some number of degrees according to Newton's law of thermal exchange, and
are used to brew the shot at the correct temp. Now, if those next few
ounces started 30F higher, while they wouldn't heat quite as rapidly while
in the HX and so not end up a whole 30F higher than the correct brew temp,
they should still be several degrees higher.

I've read advice to people with pourover HX machines that they should
insulate the reservoir from the boiler to prevent exactly this kind of
problem; is that advice just goofy (like so much espresso advice given in
these forums...)?

I'm relatively ignorant about the minutiae of HX machines; is there some
other component or part of the process that will regulate the temp back
downwards if the water starts too warm?

- David R.
--
Less information than you ever thought possible:
http://www.demitasse.net
.

Relevant Pages

  • Re: Need help dismantling Gaggia "Coffee" Boiler
    ... Thanks for all the advice. ... You've disassembled the boiler as far as you need to go. ... tablespoons in a quart of water). ... For more info on maintaining your Gaggia ...
    (alt.coffee)
  • Re: Experience with high efficiency boilers
    ...  Hot water heat, natural gas fired. ... The boiler I have now is a Peerless unit ... Clearly you have hot water heat, ... temp is below 130 F. If you have a baseboard system, ...
    (alt.home.repair)
  • Re: The one Ill be working on after Christmas...
    ... take a while before a change inside the boiler is felt on the outside. ... brew temp is much less than boiler temp in HX machine ... If boiler temp = brew temp you'd have no steam at all. ... that 230 HX does not mean 230 water leaving HX (except maybe when water has ...
    (alt.coffee)
  • Re: Gaggia not designed for long warmup? Group reaches 205F!
    ... I wonder whether priming the boiler would affect your temps. ... "portafilter wiggle" and leave the steam wand open, too, until water came ... boiler and it refilled with water. ... > water of a temp, I assume, is closer to what it should be. ...
    (alt.coffee)
  • Re: The one Ill be working on after Christmas...
    ... Better PID installations use thermowell. ... brew temp is much less than boiler temp in HX machine This is by design - 1st of all you need high temps in boiler for decent steaming. ... The water flows thru the HX briefly and only picks up a certain amount of heat so that 230 HX does not mean 230 water leaving HX. ... The real problem is lag - you want the PID to trigger the moment the water temp drops and the more remote your sensor is from the actual water temp the greater the lag. ...
    (alt.coffee)