Author Topic: Thermal mass question  (Read 469 times)

Offline Pi

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Thermal mass question
« on: December 22, 2013, 08:51:02 AM »
A typical batch uses roughly 11 gallons. Is it any more or less efficient to heat the entire amount of water at once, versus doing in batches (strike water, infusions mash out).
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Offline leejoreilly

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Re: Thermal mass question
« Reply #1 on: December 23, 2013, 07:05:05 AM »
I would imagine that it would be slightly less efficient to keep some of your water hot while waiting to use it than to heat it to temp as needed. For example, heating all 11 gallons to mash temp, then keeping the unused portion at sparge temp during the mash would cost some energy over heating the sparge water "just in time". And I don't think that heating larger volumes of water is inherently any more efficient (energy required per gallon per degree of temp) that heating smaller volumes. Also, one particular individual burner/pot (volume and geometry) set-up might have greater efficiency than another. But, at least for me, the convenience of having the water at the proper temp when I need it outweighs the slight (I imagine) efficiency costs.

I should note that I brew in my kitchen, using a gas stove. Once I get to the temp I want, I can turn the gas flame down to a "maintenance" level for as long as I need to hold that temp. I'm not sure how easy it would be to do that outside on a propane burner, or with an electric heater setup for that matter.

Offline reverseapachemaster

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Re: Thermal mass question
« Reply #2 on: December 23, 2013, 07:47:28 AM »
I should note that I brew in my kitchen, using a gas stove. Once I get to the temp I want, I can turn the gas flame down to a "maintenance" level for as long as I need to hold that temp. I'm not sure how easy it would be to do that outside on a propane burner, or with an electric heater setup for that matter.

I have not had good luck trying to maintain temperature on an electric coil stove. It seems like the coil continues to give off a lot of heat even after the coil is turned off. I always seem to overshoot target temperature if I shut off the burner at target temperature and leave the water on the burner. There's probably a certain number of degrees below target that I should shut off the burner to stay at the target temperature but I haven't figured out what it is.
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