Heat dissipation formula

Anyone have one?

Here's my problem. It's summer and the CFC wont get the wort down below 82. I have a 7 cu. ft. chest freezer and able to maintain 65 with a temp controller. If I put 6 gallons of wort in there at 82 degrees, how long to cool to 65?

(I know the correct answer is going to be "purchase a pre-chiller", but I'm curious).

a few bags of ice may make it go faster,and you wont be working the hell out of the freezer.

It depends on a number of things like the shape of the container (area vs. volume is important here) and whether the wort is being moved around or not. Deltas are the key here. Water has a high heat capacity, especially compared to air which means when cold it will be able to absorb a lot of heat from the wort. If you plop it into that chest freezer, it will get to 65, but do it often enough and I'm confident you'll eventually embrace the pre-chiller.

I agree with the ice part. If you can, put the fermenter in a bucket of water and ice. Cold water will dissipate the heat many times faster than cold air.

spiny_norman said:

Anyone have one?

Here's my problem. It's summer and the CFC wont get the wort down below 82. I have a 7 cu. ft. chest freezer and able to maintain 65 with a temp controller. If I put 6 gallons of wort in there at 82 degrees, how long to cool to 65?

(I know the correct answer is going to be "purchase a pre-chiller", but I'm curious).

Click to expand...

Not math based, but anecdotal....

When I brewed this past Monday I hit a snag with my chilling (my pump got clogged) and I had to abandoned chilling before I really wanted to. My wort went into my 62*F temp-controlled fridge at a swampy 84*F. This was around 11pm Monday night. When I got up the next morning at about 7am, the fermometer stuck to the carboy (I know... not the most accurate thing in the world) was reading 66*F, so I pitched yeast and went to work.

So... I'll quote it as "around 8 hours".