Up until now you’ve been fermenting your beer in the basement, or in that hall closet that stays nice and cool. What if you want to brew a saison that calls for higher fermentation temperature, want to try your hand at lagering, or even dial in your standard ale fermentations more precisely? You need a way to control the fermentation temperature.
Temperature control isn’t just for beers that ferment higher or lower than average. All of your batches can benefit from being at the right temperature at the right time.
Homebrewers used to have to come up with clever ways to keep fermentation temperatures in check. Take the “Swamp Cooler” method, where a fermenter is placed in a vessel of ice water and a T-Shirt is draped over it. The theory goes like this: The T-shirt draws up water, which evaporates and keeps the fermenting beer 10-15 degrees cooler than the ambient room temperature. That’s a great way to keep fermenters cool on a budget, but with a little investment, accurate, and constant temperature control is easy to achieve.
When it comes to temperature controllers, as with most aspects of homebrewing, there’s no single way to do it. And these days, it’s easier than ever to build (or buy) a temperature controller. Here’s what you need to know if you’re taking the plunge into homebrew temperature control.
My Temperature controller
There are two main types of temperature controllers: Single Stage and Dual Stage.
Single Stage temperature controllers can only control one output (heat or cold) at a time. If your only concern is keeping your fermenting beer cool in the summer, or you just need to keep your kegerator at a constant temperature this might be the way to go. Single-stage controllers also work great for lagering.
Single-stage controllers aren’t great for keeping a constant temperature during ale fermentation. Let’s say you’re fermenting in your 55-degree basement, using a single-stage controller hooked up to a heating element. With the temperature is set at 64 degrees, you’re guaranteed to never go below that. But what happens if the fermentation is active and the temperature starts rising naturally? You can try and monitor the temperature and switch from heat to cool manually, but that’s a pain. Dual-stage controllers can solve this problem.
Dual Stage temperature controllers control both hot and cold outputs at the same time. In the example above, using a dual-stage controller, the cooler would kick in once the temperature reached the threshold, keeping your fermentation chamber at the correct temperature.
Mounted digital temperature controller
Digital controllers allow you much more precision as you can set the temperature and other variables such as temperature differential. Digital controllers have a digital display. Analog controllers are less precise and usually feature a knob to change the temperature, and not much else.
Every temperature controller uses a temperature probe. There’s some debate on how to get the most accurate reading, but two approaches seem to stand out.
If you want to measure the temperature of a liquid, it makes sense to insert the probe into the liquid. This is the idea behind thermowells. For about $25, you can get a stopper that has an opening with a tube that extends down into the fermenter. The temperature probe is inserted into the tube. There is also a hood model.
If your temperature probe is too big to fit into the thermowell, or you’re saving your cash, another option is to tape the temperature probe to the side of the fermenter and then insulate the three sides not touching the glass with foam or bubble wrap.
Finally, some people suggest placing the temperature probe in a jar of water inside the chamber.
A chest freezer or mini fridge is usually used to control the cooling. If you’re going with a mini fridge, look for one that has a single door, removable shelves, no freezer compartment, or has a freezer compartment that you can easily fold down. You may also have to remove the door shelves in order to fit your fermenter inside.
If you’re going the chest freezer route, check out this forum thread on different models.
If you’re buying either a chest freezer or mini fridge second hand, ask the seller to plug it in the night before, so you know it works when you get there.
Since you’ve already got the fermentation chamber, warming your fermenter is fairly simple. Commercial products such as the Brew Belt or FermWrap wrap around the carboy or bucket and provide a source of heat. They run about $30. Of course, there’s a DIY way as well. A paint can heater is just what it sounds like. To make it, you wire up an incandescent light bulb inside an empty paint can. Place the heater in your chamber, and when the bulb turns on, the heat warms up your chamber.
This is probably the biggest question to ask when you’re shopping for a temperature controller. A store-bought dual-stage controller like this Ranco will run you $150. On the other hand, you can build the same thing using an STC-1000 for way less than half the price. It comes down to convenience (and price) vs. saving money, but spending more time building something.
Here are some commonly used temperature controllers:
Chart of most used temperature controllers for homebrewing.
Temperature control isn’t just for beers that ferment higher or lower than average. All of your batches can benefit from being at the right temperature at the right time.
Homebrewers used to have to come up with clever ways to keep fermentation temperatures in check. Take the “Swamp Cooler” method, where a fermenter is placed in a vessel of ice water and a T-Shirt is draped over it. The theory goes like this: The T-shirt draws up water, which evaporates and keeps the fermenting beer 10-15 degrees cooler than the ambient room temperature. That’s a great way to keep fermenters cool on a budget, but with a little investment, accurate, and constant temperature control is easy to achieve.
When it comes to temperature controllers, as with most aspects of homebrewing, there’s no single way to do it. And these days, it’s easier than ever to build (or buy) a temperature controller. Here’s what you need to know if you’re taking the plunge into homebrew temperature control.
My Temperature controller
Single Stage vs. Dual Stage
There are two main types of temperature controllers: Single Stage and Dual Stage.
Single Stage temperature controllers can only control one output (heat or cold) at a time. If your only concern is keeping your fermenting beer cool in the summer, or you just need to keep your kegerator at a constant temperature this might be the way to go. Single-stage controllers also work great for lagering.
Single-stage controllers aren’t great for keeping a constant temperature during ale fermentation. Let’s say you’re fermenting in your 55-degree basement, using a single-stage controller hooked up to a heating element. With the temperature is set at 64 degrees, you’re guaranteed to never go below that. But what happens if the fermentation is active and the temperature starts rising naturally? You can try and monitor the temperature and switch from heat to cool manually, but that’s a pain. Dual-stage controllers can solve this problem.
Dual Stage temperature controllers control both hot and cold outputs at the same time. In the example above, using a dual-stage controller, the cooler would kick in once the temperature reached the threshold, keeping your fermentation chamber at the correct temperature.
Digital vs. Analog
Mounted digital temperature controller
Digital controllers allow you much more precision as you can set the temperature and other variables such as temperature differential. Digital controllers have a digital display. Analog controllers are less precise and usually feature a knob to change the temperature, and not much else.
Temperature Probe Placement
Every temperature controller uses a temperature probe. There’s some debate on how to get the most accurate reading, but two approaches seem to stand out.
If you want to measure the temperature of a liquid, it makes sense to insert the probe into the liquid. This is the idea behind thermowells. For about $25, you can get a stopper that has an opening with a tube that extends down into the fermenter. The temperature probe is inserted into the tube. There is also a hood model.
If your temperature probe is too big to fit into the thermowell, or you’re saving your cash, another option is to tape the temperature probe to the side of the fermenter and then insulate the three sides not touching the glass with foam or bubble wrap.
Finally, some people suggest placing the temperature probe in a jar of water inside the chamber.
Cooling Your Fermenter
A chest freezer or mini fridge is usually used to control the cooling. If you’re going with a mini fridge, look for one that has a single door, removable shelves, no freezer compartment, or has a freezer compartment that you can easily fold down. You may also have to remove the door shelves in order to fit your fermenter inside.
If you’re going the chest freezer route, check out this forum thread on different models.
If you’re buying either a chest freezer or mini fridge second hand, ask the seller to plug it in the night before, so you know it works when you get there.
Warming Your Fermenter
Since you’ve already got the fermentation chamber, warming your fermenter is fairly simple. Commercial products such as the Brew Belt or FermWrap wrap around the carboy or bucket and provide a source of heat. They run about $30. Of course, there’s a DIY way as well. A paint can heater is just what it sounds like. To make it, you wire up an incandescent light bulb inside an empty paint can. Place the heater in your chamber, and when the bulb turns on, the heat warms up your chamber.
DIY vs. Store-Bought
This is probably the biggest question to ask when you’re shopping for a temperature controller. A store-bought dual-stage controller like this Ranco will run you $150. On the other hand, you can build the same thing using an STC-1000 for way less than half the price. It comes down to convenience (and price) vs. saving money, but spending more time building something.
Temperature Controllers:
Here are some commonly used temperature controllers:
Chart of most used temperature controllers for homebrewing.