RunBikeBrew
Well-Known Member
I've got a Belgian Dubbel fermenting right now and I've had some trouble controlling the temperatures as accurately as I'd like. I would like to hold fermentation at 64F, then gradually increase (~1F/day) over a week. This got me thinking...
Here are the temperature control tools at my disposal:
1. Aquarium heater & water bath: min thermostat setting is around 67F
2. Son of Fermentation Chiller: max temp setting is the same as ambient (see #3)
3. Ambient conditions in my basement (T=61F)
The problem: how to control temperatures between 61F and 67F?
Complicating factors:
- Fermentation is exothermic, and apparently fairly nonlinear - i.e. warmer fermenation generates more heat, cooler fermentation generates less heat.
- This is a transient problem. I need to carefully balance heat input, heat lost, and heat generated...all while each varies with time and temperature.
If I leave the Dubbel unheated, it will drop to around ambient temp (61F, too cold). If I plug in the heater, it rises to 70F (too hot). Right now, I'm trying a relatively simple solution: I put the aquarium heater in a 1 gallon plastic bucket full of water, then suspend the bucket so that only about 1/3 of it is immersed in the "big" water bath. Hopefully, this lets some of the heat dissipate to the air and not heat the wort. We'll see...
The way to solve this problem would be to develop a system that senses the temp of the fermenter, then supplies heat or cold as appropriate to maintain temperature. Here's a thought: I could have a "main" water bath for the fermenter, a separate bucket with an aquarium heater, and another bucket with ice water. Then provide a control system that senses temp and pumps water from either the hot or cold reservoirs to control temp. However, I my existing thermostat mods only support controlling one side (i.e. heating or cooling). I suppose I could use two thermostats.
Any great ideas out there?
(The other way to solve this is to only brew beers that require ferm temps substantially above or below ambient temp. Looks like I need to do a lager...)
Update: Here's one solution: https://www.homebrewtalk.com/f51/side-side-fermentation-chamber-build-105054/#post1152770
Here are the temperature control tools at my disposal:
1. Aquarium heater & water bath: min thermostat setting is around 67F
2. Son of Fermentation Chiller: max temp setting is the same as ambient (see #3)
3. Ambient conditions in my basement (T=61F)
The problem: how to control temperatures between 61F and 67F?
Complicating factors:
- Fermentation is exothermic, and apparently fairly nonlinear - i.e. warmer fermenation generates more heat, cooler fermentation generates less heat.
- This is a transient problem. I need to carefully balance heat input, heat lost, and heat generated...all while each varies with time and temperature.
If I leave the Dubbel unheated, it will drop to around ambient temp (61F, too cold). If I plug in the heater, it rises to 70F (too hot). Right now, I'm trying a relatively simple solution: I put the aquarium heater in a 1 gallon plastic bucket full of water, then suspend the bucket so that only about 1/3 of it is immersed in the "big" water bath. Hopefully, this lets some of the heat dissipate to the air and not heat the wort. We'll see...
The way to solve this problem would be to develop a system that senses the temp of the fermenter, then supplies heat or cold as appropriate to maintain temperature. Here's a thought: I could have a "main" water bath for the fermenter, a separate bucket with an aquarium heater, and another bucket with ice water. Then provide a control system that senses temp and pumps water from either the hot or cold reservoirs to control temp. However, I my existing thermostat mods only support controlling one side (i.e. heating or cooling). I suppose I could use two thermostats.
Any great ideas out there?
(The other way to solve this is to only brew beers that require ferm temps substantially above or below ambient temp. Looks like I need to do a lager...)
Update: Here's one solution: https://www.homebrewtalk.com/f51/side-side-fermentation-chamber-build-105054/#post1152770