cappuccinoboy Senior Member Joined: 27 Jun 2009 Posts: 793 Location: MILANO Expertise: Professional
Espresso: Milano pod, Milano fully... Grinder: grind on demand
Posted Fri Jun 25, 2010, 2:13pm Subject: Re: Heat exchange machine temp control
boyscout Said:
Leighton, I owned a good HX machine before purchasing a DB machine............ .................
....... The HX machine's typically-massive group resists temperature change - that is its job, after all - and it usually gets heated by conduction, rather than the direct heating of brew water by a heater that occurs in a DB.................... Hope this helps.
I expected no less of you ............. ............
Again, you re-make my point. Just as I said, your group is heated by conduction of temperature (from the water), it's big and heavy, and takes some time to change temperature. A DB's brew water is directly and quickly brought to temperature by an electric heater, ............
..........................
I'm glad you are happy with your machine, really. We'd be more likely to believe it though if you got off the "HX owners all have a secret lust for a DB, buy one now and save a step in the upgrade path" soapbox and recognized that there are at least 2 of us, maybe more, that enjoy the process as much as the coffee and are as happy with our machines as you are with yours.
It made me smile that so much passion could be put into this matter based on a totally wrong assumption.....brew group is kept hot (in HX and DB machines) basically to "keep" brew water at the right temperature : it is NOT the brew group that brings water to brew temperature...., while a cold group would easily "suck" heat from brew water.......I'd love to hear Bill Crossland's opinion, since he is working on a concept that gets away with heavy mass and big boilers... so he does not waste energy to warm them and keep them warm.....but probably he was just L(ing)OL... Ciao everybody, Pietro
Posted Fri Jun 25, 2010, 2:25pm Subject: Re: Heat exchange machine temp control
cappuccinoboy Said:
It made me smile that so much passion could be put into this matter based on a totally wrong assumption.....brew group is kept hot (in HX and DB machines) basically to "keep" brew water at the right temperature : it is NOT the brew group that brings water to brew temperature....
Something must have been lost in the translation, I don't think that anybody has ever claimed that the group brings the water to brew temp. How could a chunk of metal that is heated by water that is already heated possibly heat that same water? I did however,get a chuckle out of your post, it seems to be based on a "totally wrong assumption." ;)
cappuccinoboy Senior Member Joined: 27 Jun 2009 Posts: 793 Location: MILANO Expertise: Professional
Espresso: Milano pod, Milano fully... Grinder: grind on demand
Posted Fri Jun 25, 2010, 3:04pm Subject: Re: Heat exchange machine temp control
davethebrewguy Said:
Something must have been lost in the translation, I don't think that anybody has ever claimed that the group brings the water to brew temp. How could a chunk of metal that is heated by water that is already heated possibly heat that same water? I did however,get a chuckle out of your post, it seems to be based on a "totally wrong assumption." ;)
Dave you should read carefully what Boyscout said ref brew group and DB "direct" heating system...., and, since it is your mother language, report to me if I did misunderstand.......in which case you will excuse me as an ignorant foreigner....... Ciao, Pietro
I have a group thermostat on my VBMDD, and I too can do some 'on the fly' temp adjustments (a window of 5F is possible) while still maintaining a 1F intrashot variance, but anything greater than 5 degrees requires a 10 minute or more wait due to the brass chunk. I don't see how an HX can do a fully stable 5+ degree change instantly. While totally impractical, I can turn off the PID and dump a huge portion of boiler water rendering my boiler well below the group temp as it would occur similarly to an HX, and the E61 is STILL the gatekeeper. .
And amongs the claims we've all been making I'm still waiting with some actual data on "on the fly" temp adjustments that seems to be in question. Anyone? Bueller?
Posted Fri Jun 25, 2010, 3:45pm Subject: Re: Heat exchange machine temp control
Not verbatim, but:
but anything greater than 5 degrees requires a 10 minute or more wait due to the brass chunk. {snip} and {snip} and the E61 is STILL the gatekeeper.
Were these meant to be used as examples of a comment that asserts that the E61 is a "heat source?" The E61 could be referred to as a "buffer" but I see no mention of the brew group being used to heat the water.
Yes. Perhaps I didn't supply enough context of the quotes between Al and myself. Al (and if I misunderstood my appologies), was claiming that "on the fly" temp adjustments weren't possible on a HX because the group evens out the temp from colder water. Brewing too hot is always possible with a HX.
Guess I emphasized the wrong portion.
wideasleep1 Said:
While totally impractical, I can turn off the PID and dump a huge portion of boiler water rendering my boiler well below the group temp as it would occur similarly to an HX, and the E61 is STILL the gatekeeper.
Outside of speculation here, is there anyone who's actually measured the brewing temps with a Scace or other device? Is the 5deg range all that can be expected?
Here the possible brewing temps meaning the same; how cool or hot can you adjust brew temps on an HX from on the fly method.
EDIT: by "data" I'm not looking for documented charts or log sheets. Rather has anyone actually used something along the lines of a Scace (or other) that gives the brewing tempature range on an HX. Erics thermometer doesn't measure the water at the coffee.
boyscout Senior Member Joined: 29 Dec 2009 Posts: 404 Location: Toronto Expertise: I like coffee
Posted Sun Jun 27, 2010, 6:50am Subject: Re: Heat exchange machine temp control
Leighton, it's not clear if you ever returned to this thread you started. Given the nasty street-fighting started (again!) by a couple of HX's advocates, and their confusing and exaggerated and even contradicting claims, who could blame you?
However if you are still following this, and still looking for advice, I've just seen this thread that I had missed:
A number of people there managed to voice pleasure with double-boiler machines without having the HX muggers pile in, and they make useful points that are worth considering if you are still trying to decide which type of machine is best for you.
The thread was started in mid-May... change of seasons... maybe the HX muggers missed it because they were too busy trying to re-learn to get stable temperatures from their HX machines as the weather changed. <grin>
Joel_B Senior Member Joined: 9 Oct 2007 Posts: 1,823 Location: Pacific NW Expertise: I love coffee
Espresso: Astra Mega II Grinder: Mazzer SJ, Virtuoso Vac Pot: Yama 5 cup Drip: nope, french press Roaster: Behmor, WP, BBQ drum
Posted Sun Jun 27, 2010, 8:04am Subject: Re: Heat exchange machine temp control
I like the on the fly (I'm still not convinced that it's not possible) of the HX, so I'd definately weigh that in if/when I upgrade. But when will someone come out with a 2 group triple boiler machine? Seriously, I'd go for that. 2 brew boilers dedicated to each group and 1 for steaming. Or does it already exist?
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