IBC Fermentation Temperature Control

[Gundog48]

Well, we're finally taking the step from GNS gins into fermentations, our distillery is currently developing a line of rums and it's all very exciting. We're currently doing development work with 50L fermentations which we just keep in a temperature controlled room, the plan is to scale up to ~800L fermentations in 1000L plastic IBCs. The temperature in the facility varies wildly year-round from about 7°C in winter to 30°C in summer. We want to keep fermentation temperatures in the 25-35°C range, with fermentations that last about 4 days. We've got no experience with fermentations that big, and the heat loss and heat production are a bit of an unknown quantity. We're hoping that most of the year round we can simply control the pitching temperature so that it stays within the required range. Most of the year, this will probably involve warming it up to about 25°C before pitching. What I don't know is whether we'd need to insulate, or exactly what temperature we should pitch at depending on outside conditions. Does anyone have any examples on, for example, the fermentation temperature in an IBC pitched at 20°C in a 20°C room? 

It would be easy enough for me to experiment with the rate of heat loss by filling an IBC and tracking the temperature, but I don't know how much heat will be produced by the fermentation to offset the loss. Can anyone share their experiences? 

[adamOVD]

submersible aquarium heaters work great for heating rum fermentations.  1 should be enough to hold 800L at 30C.

[captnKB]

id agree with @adamOVD . a properly pitched ferment with a small aquarium heater should have no problem finshing the ferment at the desired temp

[Gundog48]

On 11/18/2019 at 3:39 AM, captnKB said:

id agree with @adamOVD . a properly pitched ferment with a small aquarium heater should have no problem finshing the ferment at the desired temp

What kind of sized heater are we talking, just a 300W one or bigger?