7 Ways to Control Your Fermentation Temperature (Without Going Over Budget)

One of the hardest things about being a home brewer is brewing the kind of beer you want to brew without breaking the bank. A home brewer’s budget can be an incredibly limiting factor, especially when it comes to investing in equipment.

There is no place in brewing where this is as easily illustrated as it is in temperature control. Because temperature control makes such a significant difference in the quality of your brew, it is easy to believe that you need to sink a ton of money into it to improve your beer. Even a modest investment of time and/or money into fermentation temperature control can reap you huge rewards when it comes to the overall quality of your beer.

While it is true that investing in the right fermentation equipment to control your temperature will get you excellent results, there are actually a lot of ways to control the fermentation temperature of your beer without breaking the bank. Here are seven ways to hit your temperature without breaking the budget.

1. Swamp Cooler

Swamp coolers are a type of air conditioner that adds humidity to the air to help the temperature feel lower than it really is. This method is called evaporative cooling, and can also be used to lower the temperature of your fermenters.

Simply put your fermenter in a pan of water. Soak a T-shirt in the water and place it over your fermenter, making sure that the bottom of the shirt dips into the water all the way around. Place a fan blowing on this, and your fermenter will hold a temperature about 10-15 degrees below ambient temperature. While this will work, it must be noted that they are very unreliable and may have a hard time holding a consistent temperature.

2. Ice Bath

Some brewers will submerge their fermenter nearly to the level of beer in the fermenter and then use frozen bottles of water to help regulate the temperature. For this trick, you’ll need a large rubbermaid or other tub (some towels under it wouldn’t be remiss, either), some water, some frozen water bottles and some ice. Using the ice and frozen water bottles to lower the temperature of the water should also keep the temperature of your fermenter down.

Frozen water bottles are recommended here, as they are larger chunks of ice that won’t melt as fast as small ice cubes. If you prefer to stick with ice cubes, you will need to have a steady supply of ice. This will increase your budget as you will have to buy lots of ice or purchase an ice maker that will produce ice on demand.

For added effectiveness, you can always go a step further by combining this method with the wet T-shirt trick and a fan to use the evaporative cooling from the swamp cooler, as well.

3. Basements and Garages

These are common for lagering in the winter. In essence, you find any place you can that is around the right temperature and use the ambient temperature to keep the fermentation temp down. It’s great in a pinch, but can be unreliable as far as temperature consistency goes.

I use this for lagering in the winter so I don’t use up valuable space in my beer fridge. I’ve had some great results, but also some not-so-great results. It all depends on the climate you live in and how consistent the temperature is throughout the fermentation process.

4. Build Your Own Refrigerator

Building your own refrigerator is as old as lagering itself. As a matter of fact, the original lager brewers used this method to make their beer. In Germany, there are Kellerwelds (cellar hills) in which caves have been carved in the hillside (like hobbit holes for beer). In the winter, the caves were opened up with the beer to be aged inside to keep them cool. As the weather warmed up, the brewers would pack snow in a special ditch carved in the side of the cavern and then they would seal them up, creating makeshift refrigeration.

To do this at home, find a cardboard box or other container big enough for your fermenter and for air to circulate around it. Cut a hole in the side and put in a little “shelf” to hold some ice. It will need to be waterproof, and it helps if the ice is inside a container, such as a water bottle or ziploc bag. Set up a fan that draws air over the ice and into the box, where it will be circulated.

For this kind of setup, it helps to have a temperature sensor inside the box that controls the fan, and it also helps to regularly change out the ice. When done right, this method works very well, but it is complicated to do correctly.

5. The Brew Belt

The methods above will all help you keep it cool, but you may also need to heat things up in your fermentation room. If you’re using a basement or closet that gets a bit cool, you can always use a Brew Belt to keep your fermentation at the target range.

The Brew Belt is an electric heating device that wraps around your fermentater. Once you plug it in, it heats up and maintains a temperature that is approximately 10° higher than the temperature of the room. You can adjust this by moving the belt up or down the side of the fermenter. If you want some additional control, you can always put a thermowell inside the bucket and set a temp sensor to kick off the Brew Belt if your fermenter reaches a target heat.

You can also just combine the Brew Belt with a thermometer that sticks to the side of the fermenter, as well. Then, you can adjust the brew belt up or down on the side of the fermenter as needed to regulate the temperature.

Note for those using carboys: Using a Brew Belt on a glass carboy is not recommended. If you decided to use this method to control the temperature, then you should stick with PET carboys.

6. Space Heater

This is a common way of keeping your beer warm in a basement or closet, and is sometimes paired with one of the other methods for cooling beer to try and hit a tighter area of control. The space heater heats the ambient temperature of the room, which is a little slow to heat the actual liquid in your fermenter, but those gradual changes can actually be beneficial, as moving the temperature too fast can cause your yeast to freak out.

Space heaters have a lot of risks, though. Using a space heater safely is essential. Some shut off automatically to prevent fires, and others may actually catch fire if left in a room without supervision. You should also check the manufacturer’s guide before attaching any kind of “power” control to one. Using a temperature controller on a space heater can be a fire hazard or it may just break your heater.

7. Use an Old Fridge or Freezer

It may seem like a no-brainer, but finding a used refrigerator or freezer and adding a temperature controller is one of the best ways to achieve great temperature control throughout the fermentation process. Whether you need to keep it cool or warm, the insulation of a refrigerator will help you maintain a consistent temperature.

Obviously, to cool it down you will plug it in and set it to your desired temperature. However, if you want to keep it warm inside, try using a miniature space heater to help you control the temperature. Either way, the you can effectively control the temperature inside the refrigerator incredibly well.

One of the best ways to find a used fridge or freezer for not much money is to watch want gets posted on Craigslist. You can find some amazing deals on there, but you typically have to be pretty quick and patient, as well as deal with some sketchy people. You can also check out scratch and dent websites or outlet stores in your area that carry appliances. You may get a unit that has a cosmetic defect, but if you got it at a deep discount, does it really matter?

No matter how you go about it, watch for the deal that fits your budget and then be ready to pounce on it. I’ve known a few brewers who picked up deep freezers or beverage fridges for free when the owners just wanted them out of the way. For that, you have to be lucky and fast.

What about you? How do you control your temperatures? Let us know in the comments.