3.5 BBL chilling / Heating ?

[BlackMammoth]

Hey folks. I'm in the process of opening a small 3 bbl nano tasting room only. I live in a high tourism mountain town and have a commercial space with heavy foot traffic in front. My question is about fermenter heat.

We will be Trying to keep the brewery near room temp since it is the same space as the tasting room. But with climate here I wouldn't be surprised if the temp were to dip to 60-65 at night (unless I did overkill on space heaters but that comes with a high electrical price). I will be fermenting in 150 gallon plastic fermenters from plasti mart. My homebrew setup requires me to have heat pads under the Carboy and a space heater nearby to keep a ferment temp of 68-72. But all I hear about in the professional brew world is the use of chillers and how fermentation raises the temp naturally.

What would you guys expect a 3.5 bbl batch to ferment at in those conditions? What options would I have for heating them if needed? I would like to do diacetyl rests at 72 after most the primary fermentation has occurred. Would the ferment still be putting off heat at that stage?

The brewery down the road has 15bbl and 30bbl ss jacketed fermenters sitting outside where the temps in the winter can get to 20-30 degrees. Are they able to perform diacetyl rests like that?

Thanks for the help!

[oswiu]

Hi!
I've been operating a 4hL (about the same size as yours) brewery in Wellington, NZ for a few months now, and have just fermented a beer that might provide a bit of real-world info for you:

We use double-skinned but (for the moment at least) un-insulated stainless fermenters. In the summer we run glycol through the skins to keep them cool. However just recently I brewed a Belgian beer where I pitched the yeast at 24C (around 75F) and set the fermenter temp to 26C (79F). The ambient temp in the brewery at this point probably averaged around 18-20C (66F). During the peak of fermentation, the heat JUST raised the temp of the beer enough that the glycol became necessary in short bursts. Once the ferment was within about 4 points of expected finishing gravity I turned the glycol right off, but the temperature in the fermenter just slowly dropped to ambient.

It will depend on tank geometry and material (I imagine your plastic will insulate better than our stainless), and on the exact ambient and ferment temps. But from this experience it appears that a ~3.5bbl batch can generate enough heat to keep you maybe 10F above ambient when it's really going. But once fermentation starts to die down, you probably can't expect it to bring you up much for a D-rest.

The bigger guys manage okay because:
1. Their tanks are insulated and retain much of the heat of fermentation unless the glycol carries it away
2. Their bigger tanks have bigger volume to surface area (i.e. heat generated to heat lost) ratios

My first thought for how to deal with your issues would be to insulate your fermenters, see how that works, then carry on from there. It appears we may well be headed down the same road once winter really sets in down here!