| Author |
Message |
    
Walt Fischer (24.221.196.114)
| | Posted on Sunday, March 30, 2003 - 09:28 pm: | 
|
Sooo what type of temp raise occurs from the fermenting process? How exactly does fermenting raise the temp?
Bill? 
Walt
---- |
Fredrik (213.114.44.196)
| | Posted on Sunday, March 30, 2003 - 10:53 pm: |
|
I don't know the details but as far as I understood (beware that I am new to brewing myself so don't take my word for it) most of the heat beeing released during fermentation is from oxidation of glyceraldehyde-3-phosphate, beeing a intermediate in glycolysis. Glycolysis is the sub process chain where glucose is converted to puryvic acid. Next (alcoholic fermentation) puruvic acid is converted into etanol, but I don't think this releases any significant heat.
I do not have any experience regarding temperature but I think I've seen other people report temperature inside the bucket beeing something like 2-3 degrees higher than the ambient temperature? Otherwise I trust you could calculate it from the specific heat release during glycolysis.
http://www.sp.uconn.edu/~bi107vc/fa02/terry/metabolism.html
is an link I found that I like
/Fredrik |
don price (65.32.41.146)
| | Posted on Monday, March 31, 2003 - 12:42 am: |
|
Skipping the chemistry and straight to practical thermodynamics....my memeory and relatively limited personal experience indicates a temperature rise of 5-10 F above ambient temperatures during peak fermentation (first 24-72 hours?) in 6 gallon carboys. Please note that high gravity brews that start relatively warm (say 1.080 imperial stout on a WY1056/WLP001 yeast cake at 75 F - not a good idea) will give a much higher temperature rise than a lower gravity beer started with less yeast at a lower temperature. Start low and slow enough and you won't get much temp rise, or fermentation, at all. Temperature affects flavor so I won't try to tell you what is right for you.
Don |
Bretth (12.253.241.217)
| | Posted on Monday, March 31, 2003 - 02:00 am: |
|
You kill me, Fred! |
Brandon Dachel (208.44.235.190)
| | Posted on Monday, March 31, 2003 - 01:30 pm: |
|
> How exactly does fermenting raise the temp?
It's an exothermic reaction. |
Bill Pierce (208.57.122.28)
| | Posted on Monday, March 31, 2003 - 03:59 pm: |
|
Exactly. Most organic reactions are exothermic, that is, they release energy in the form of heat. Think of the reactions in the body when we metabolize food. |
Brews and Views Archive 2003