Thursday 23 June 2022

How to Heat in a Fermentation Fridge

It's well known that temperature is a critical variable when it comes to fermentation - the magical process performed by brewing yeast that turn wort into beer. The process of fermentation is exothermic - a fancy word meaning it creates heat, so for most homebrewers the a simple solution to control the temperature during fermentation is to purchase a new or second hand fridge that the fermenter can be placed into, and then controlled with a temperature controller like an Inkbird.

Simple, effective and efficient as this is - what if the ambient temperature is well below our target fermentation temperature so we need to add a heat source to help raise the temperature of our fermenter within the fridge instead of reducing it like you normally would?

This is the situation we face for a few months each year during the colder winter months where temperatures are constantly below the typical ale fermentation temperature of 18-20 degrees. We were about to embark on the maiden brew on our recently purchased Cheeky Peak Nano-X Fermenter and knew we needed a heat source to maintain our target fermentation temperature.

There are plenty of options for heating fermenters - heat pads, heat belts, glycol chillers/heaters, light/heat lamps, space heaters - the list goes on and on. Since our fermenter was made of stainless steel, we weren't comfortable wrapping a heat belt around it. Glyocol chillers/heaters are expensive, and sitting a space heater inside a fridge really didn't seem like a great idea either.

We opted for a heat pad which appeared to be a relatively safe and gentle method of warming the space inside the fridge. A bit of research and we settled on the Morgan's Heat Pad - offering 25W of heating power.

We sat it inside the fridge and situated it in between the legs of the fermenter and actually had it resting on the legs. This way the heat would radiate directly up and onto the conical bottom of the fermenter. 

Raising the temperature in a full size fridge with a relatively low heat source like this can be slow, but it does work. We also used the insulating jacket from our FermZilla as an additional layer of insulation to help trap the heat in and around the fermenter as you can see from the photo below. Sure, it doesn't fit properly but it certainly helped and we were able to reliably maintain a temperature of 20 degrees celsius, even when the ambient temperature outside was well into the single digits.

Our Cheeky Peak Nano-X with Morgans Heat Pad

At the end of fermentation we were also able to raise the temperature to 22 for a diacetyl rest with no problems at all.

For those who haven't used a heat pad before, we'd best describe it as getting warm at best, and not hot. So the heat it produces is gentle, and safe. It can comfortably be touched without any risk of burns whilst being powered. That being said, it means it works somewhat slowly, so anything you can do to assist in the retention of heat is going to help with the heating efficiency. Simple things like adding a jacket or any other form of insulation around the fermenter is a great start. The other obvious thing is to resist the temptation to constantly open your fermentation fridge to check how things are going which let's all the warm air out!

We're happy with this current setup being safe, effective and reasonably efficient to help us warm our fermenter. Not sure a heat pad like this could provide enough heat for Kveik fermentation temperatures during winter, so perhaps save those ones for the warmer months of the year.

Related Articles

Other Brewing How-To Guides, Tips & Tricks

No comments:

Post a Comment