fermentation exothermic?

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anderj

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Always at the risk of sounding dumb, is fermentation just a bit exothermic? I have a batch five days in the primary (still super active) sitting next to a stout that has been in secondary for 1.5 weeks. The temps indicated for the primary and secondary are 72 and 68 respectively. The carboys are about 12 inches apart. Just seems odd. I am using the fermometer stick-on type temp gauge. Also empty carboy in the vicinity reads at 66 but that is more responsive to short term small temp fluctuations (heat kicking on and off)
 
You can really see this with the extremely active ferments (as expected).
 
Yeast are alive. + Sugar -> Booze, bubbles, heat

Most commercial fermenters have cooling coils, otherwise it would be -> Hooch, explosions, autolyse
 
First, we need
to know how the mass of Hell is changing in time. So, we need to know
the rate that souls are moving into Hell and the rate they are leaving.
I think that we can safely assume that once a soul gets to Hell, it
will not leave. Therefore, no souls are leaving. As for how many souls
are entering Hell, let's look at the different religions that exist
in the world today. Some of these religions state that if you are
not a member of their religion, you will go to Hell. Since there are
more than one of these religions and since people do not belong to
more than one religion, we can project that all people and all souls
go to Hell. With birth and death rates as they are, we can expect
the number of souls in Hell to increase exponentially.
Now, we look at
the rate of change of the volume in Hell because Boyle's Law states
that in order for the temperature and pressure in Hell to stay the
same, the volume of Hell has to expand as souls are added. This gives
two possibilities.
1) If Hell is
expanding at a slower rate than the rate at which souls enter Hell,
then the temperature and pressure in Hell will increase until all
Hell breaks loose.
2) Of course,
if Hell is expanding at a rate faster than the increase of souls in
Hell, then the temperature and pressure will drop until Hell freezes
over.
So which is it?

If we accept the
postulate given to me by Ms. Therese Banyan during my Freshman year
"That it will be a cold night in Hell before I sleep with you," and
take into account the fact that I still have not succeeded in having
sexual relations with her, then (2) cannot be true, and thus I am
sure that Hell is exothermic.
 
MikeFlynn74 said:
First, we need
to know how the mass of Hell is changing in time. So, we need to know
the rate that souls are moving into Hell and the rate they are leaving.
I think that we can safely assume that once a soul gets to Hell, it
will not leave. Therefore, no souls are leaving. As for how many souls
are entering Hell, let's look at the different religions that exist
in the world today. Some of these religions state that if you are
not a member of their religion, you will go to Hell. Since there are
more than one of these religions and since people do not belong to
more than one religion, we can project that all people and all souls
go to Hell. With birth and death rates as they are, we can expect
the number of souls in Hell to increase exponentially.
Now, we look at
the rate of change of the volume in Hell because Boyle's Law states
that in order for the temperature and pressure in Hell to stay the
same, the volume of Hell has to expand as souls are added. This gives
two possibilities.
1) If Hell is
expanding at a slower rate than the rate at which souls enter Hell,
then the temperature and pressure in Hell will increase until all
Hell breaks loose.
2) Of course,
if Hell is expanding at a rate faster than the increase of souls in
Hell, then the temperature and pressure will drop until Hell freezes
over.
So which is it?

If we accept the
postulate given to me by Ms. Therese Banyan during my Freshman year
"That it will be a cold night in Hell before I sleep with you," and
take into account the fact that I still have not succeeded in having
sexual relations with her, then (2) cannot be true, and thus I am
sure that Hell is exothermic.
Oh. So that's what the hell is going on in my fermenter. ;)
 
Yes, yeast will give off heat during fermentation. A temperature rise of 7-10° is not uncommon at high krausen. Among other things, the higher the temperature of the wort at pitching (along with ambient temperature) the greater the rise will be. This is due to the yeast being more active at higher temperatures. This is why it is wise practice to pitch the yeast into wort that is at or a little below the so called "minimum" temperature range of the yeast. The recommended fermentation temps on the yeast packages are ideal for yeast growth and health as opposed to being ideal for good beer.

Wayne
Bugeater Brewing Company
 
Bugeaterbrewing said:
The recommended fermentation temps on the yeast packages are ideal for yeast growth and health as opposed to being ideal for good beer.

Bugeaterbrewing - Great reply. I'd really appreciate if you'd spell this out for me. I think the key point is that despite what White Labs or others may state on the bottle - ex "ferment at 70-75F" - you are better off at a somewhat lower wort temperature?

Also, the atmosphere (air or water bath) around the Primary needs to be a few degrees cooler that your planned fermentation temperature.

Ex -
Yeast bottle says: 70-75 F
Better beer at: 65-70 F
Pitch yeast into wort at temp: 65-70 F
Primary in water bath at: 60-65 F during wild fermentation
Primary in water bath at: 65-70 F after wild fermentation

Thanks,
OneShoeBrew
 
So I'm based in New Zealand and right now it's winter. I do not have any heating where my fermenter is and often it drops a little below 18c. As long as it's still fermenting is this OK? Or should I be careful about how low my temp drops.
 

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