Fermentation chamber temp HELP!!!

So i have a fridge i converted to a ferm chamber with temp controller. Question is what do i set my temp controller to, if i set it to 18C at the
start of fermentation when the yeast takes off (US 05) it creates so much energy the crystal temp strip on my primary reads 20-22C. But when the yeast calms down after 4 days or so it seems to settle back down to 18C.

Should i be setting the controller to 16C for the first few days to compensate the heat bought on by vigorous fermentation, then back to 18C when it slows down??

Did i make any sense?

What I believe many people do, and I do, is to attach the temp probe from your temp controller to the side of your fermenter. Surround the probe with insulation like foam or something similar, and the probe should reflect the temp of the fermenter itself and not the surrounding air. Doing it this way, your temp controller will control your fridge to maintain the temp of the brew. You will probably see the fridge drop in temp initially to compensate for the active fermentation, but then over a few days will work back up. During this time your brew will stay a constant temp.

Another trick I've read some people do is to put their probe in a glass or pitcher of water. This method though wouldn't compensate for active fermentation temperature rise then fall.

Hope that helps!

jaspass said:

What I believe many people do, and I do, is to attach the temp probe from your temp controller to the side of your fermenter. Surround the probe with insulation like foam or something similar, and the probe should reflect the temp of the fermenter itself and not the surrounding air. Doing it this way, your temp controller will control your fridge to maintain the temp of the brew. You will probably see the fridge drop in temp initially to compensate for the active fermentation, but then over a few days will work back up. During this time your brew will stay a constant temp.

Another trick I've read some people do is to put their probe in a glass or pitcher of water. This method though wouldn't compensate for active fermentation temperature rise then fall.

Hope that helps!

Click to expand...

AWESOME! Thanks a lot, one step closer to better beer

The first thing you need to do is starting using Fahrenheit...:cross:

Tape is to the side of the carboy, insulate it, and whatever you do don't ever believe the crystal strips.

Xpertskir said:

The first thing you need to do is starting using Fahrenheit...:cross:

Tape the probe to the side of the carboy, insulate it, and whatever you do don't ever believe the crystal strips.

Click to expand...

+1. You can get a block of foam insulation at the home improvement store. Look for closed cell rigid insulation. Cut off a block and cut a recess in it to entirely enclose the temp probe and permit it to come in full contact with the bucket temp. I did a temp study once where i compared the bucket probe temp to that of a probe inserted directly into the wort. The wort was consistently 2 degrees F higher than the outside of the bucket. Something to think about when selecting your temp setpoint.

thats why I just picked up this http://www.williamsbrewing.com/THERMOWELL-FOR-PLASTIC-CARBOYS-P2596.aspx. I wont have to guess or adjust. It stands to reason to me that the more vigorous the fermentation the larger the difference between the center and outside of the wort.

Xpertskir said:

thats why I just picked up this http://www.williamsbrewing.com/THERMOWELL-FOR-PLASTIC-CARBOYS-P2596.aspx. I wont have to guess or adjust. It stands to reason to me that the more vigorous the fermentation the larger the difference between the center and outside of the wort.

Click to expand...

When fermentation is vigorous, there is very little temp difference, because of the churning action. It looks like a rolling boil. As it dies down, there will be more difference between the center and side/top/bottom.

I've found if the cooling medium is air, control based on the carboy/beer temp. If the cooling medium is liquid, control the liquid temp. This is because air changes temp much quicker than liquid.
Wild air temp swings don't impact the beer temp much, but wild swings in a liquid bath (swamp cooler) result in much greater carry over to the beer, and less stable beer temp.

I thought I'd add a picture to illustrate measuring and controlling the water bath temperature. If I measured the carboy temp, this would look like an earthquake.

In this you can see at the starting point I was at 74 F, which is the best I can get with 72 F water until temps cool the ground water later this fall.
I try to get it cooled as quickly as possible. Once the internal carboy temp dropped to 66 F, I set the temperature controller to my target.
My target temp was 65 F. During peak activity, I've found the carboy temp stays along the peaks of the water bath temps. It reaches around 65.25 F as an average high.
Once active fermentation is over, the carboy temp tends to drift down to the midpoint of the water bath cycles. At this point I set the temp controller one degree higher, to keep the temp closer to the 65 F target.
Overall though, we're talking much less than a degree drift when measuring and controlling the water bath temp as opposed to the carboy temp.

This all happens within 48 hours. Incidentally, this is WLP380 pitched cold, after a four day crash cool so I could decant it without losing too much of the low floc portion. 1.052 OG. Shake method aeration. Took off quickly.