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I have 5 BBL FV's with one jacket that starts at the cone and goes most of the way up the side wall. I believe one jacket is the standard design for the smaller FV's. The normal glycol piping design appears to have the cold glycol coming in the bottom of the jacket and leaving out the top.
On a recent batch we noticed every time the temperature controller opened to cool the FV by about 2 degrees, all bubbling from fermentation would stop for a few hours.
This was strange so I did a test with water on an open fermenter. I found that when the glycol solution (at 40F) enters the cone section jacket from the bottom it cools the liquid in cone part of the FV to 55F. This colder liquid sinks to the bottom and the temperature by the temp probe will still show 68F. It's not until the whole cone is cooled to a low temperature, does the temperature controller close the glycol valve. The upper part of the FV will only be cooled slightly. After a few hours the FV temperature will average out.
Has anyone else found that having the cold glycol solution coming in from the bottom cools the cone section too much, while leaving the upper section warmer?
The Temperature probe is just above the transition from cone to straight wall. If the glycol enters from the top, this over cooling of the cone section does not occur. I realize if the fermentation is active enough this will not make much of a difference as the liquid will be able to mix, but if the yeast is fermenting in the cone section then it can be over cooled and become dormant, even though the average FV temp is 68F.
On a recent batch we noticed every time the temperature controller opened to cool the FV by about 2 degrees, all bubbling from fermentation would stop for a few hours.
This was strange so I did a test with water on an open fermenter. I found that when the glycol solution (at 40F) enters the cone section jacket from the bottom it cools the liquid in cone part of the FV to 55F. This colder liquid sinks to the bottom and the temperature by the temp probe will still show 68F. It's not until the whole cone is cooled to a low temperature, does the temperature controller close the glycol valve. The upper part of the FV will only be cooled slightly. After a few hours the FV temperature will average out.
Has anyone else found that having the cold glycol solution coming in from the bottom cools the cone section too much, while leaving the upper section warmer?
The Temperature probe is just above the transition from cone to straight wall. If the glycol enters from the top, this over cooling of the cone section does not occur. I realize if the fermentation is active enough this will not make much of a difference as the liquid will be able to mix, but if the yeast is fermenting in the cone section then it can be over cooled and become dormant, even though the average FV temp is 68F.
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