The Ultimate Guide to Fermentation Chamber

Alcoholic fermentation is a yeast-driven reaction that generates alcohol, energy, and carbon dioxide. Energy, in this case, manifests as heat, raising the temperature in the fermentor by a few degrees. To restore fermentation temperatures to the recommended levels, you’ll need a fermentation chamber.

A fermentation chamber is a gadget that regulates fermentation temperatures. Apart from temperature control, a fermentation chamber can have extra features. Light protection and temperature monitoring are some functions offered by fermentation chambers.

Can you make a DIY fermentation chamber? If so, how do you do it? We have all the answers to your questions. We’ll also tackle the various kinds of fermentation chambers available to brewers. Plus, the factors you need to consider when choosing a fermentation chamber.

Importance of Fermentation Chambers

Importance of Fermentation Chambers

The primary role of fermentation chambers is temperature control. Temperature is a critical factor in fermentation. Yeast can only work effectively at specific temperature ranges. Extremely high temperatures can kill yeast, while extremely low temperatures can slow fermentation.

Your fermentor must maintain a particular temperature range for optimal yeast action. A slight deviation from these temperatures may lead to the development of off-flavors. At high temperatures, for example, yeast tends to produce fusel alcohols, which can be harsh and unpleasant to taste. These high-order alcohols ruin the flavor of the beer.

Fermentation chambers come in all forms, from simple DIY projects to sophisticated appliances. Let’s look at the kinds of fermentation chambers available to home and commercial brewers.

DIY Fermentation Chambers

A DIY fermentation chamber is one that you can build on your own. Below are some common DIY ideas for your fermentation chamber.

1. Repurposed Refrigerator or Freezer

An old refrigerator is a perfect canvas for a fermentation chamber. It is insulated, and you can easily rig a heating system. It is also ideal for lagering because it’s a fridge.

Below is a list of types of refrigerators that you can repurpose:

  • Chest freezer
  • Upright freezer
  • Mini fridge
  • Upright refrigerator and freezer combo
  • French door refrigerator

The good news is that you don’t have to get a brand-new refrigerator. You can always repurpose your old refrigerator or buy a used example from a junkyard. To repurpose an old refrigerator, follow the instructions below:

Repurposed Refrigerator or Freezer


  • An old refrigerator
  • A temperature controller
  • Heating mat
  • A drill


  1. Drill a hole through the side of your fridge.
  2. Lay your heating mat inside, at the bottom, of the refrigerator.
  3. Pass the heating mat’s wire through the hole and connect it to the temperature controller.
  4. Plug your temperature controller and refrigerator into a wall socket.
  5. Insert your fermentor into the fridge and adjust the temperature controls accordingly.

Turn up your heating mat to warm up the fermentation chamber (in the cold seasons). To cool the fermentor, turn on your refrigerator. Check out the video below to learn how to build a fermentation chamber from a mini fridge.


2. Swamp Cooler

A swamp cooler is a DIY contraption made from a bucket of water and a towel. To make a swamp cooler, follow the steps below:

Swamp Cooler Fermentation Chamber


  • A bucket (big enough to accommodate your fermentor)
  • A clean towel
  • Some water
  • A thermometer


  1. Partially fill your bucket with water.
  2. Dip a clean towel in the bucket to soak it with water.
  3. Retrieve the wet towel as you dip your fermentor into the bucket.
  4. Cover the fermentor with the damp towel. Ensure the edges maintain contact with the water.`
  5. Use the thermometer to track fermentation temperatures.

A swamp cooler regulates fermentation temperatures via heat exchange. The water absorbs the heat dissipated from the fermentation process, reducing temperatures. The wet towel acts as a wick or a water recirculation bridge.

You can also use the swamp cooler to warm your fermentor in the winter. Substitute the cold water with a warmer alternative to heat up your fermentor. While the swamp cooler is easy to build, it isn’t the most accurate fermentation chamber.


3. DIY Cold Storage Room

If you have a spare room at home, you can transform it into your cold storage room. Repurposing a space into a cold storage room is costly and laborious, but it establishes you as a brewer. Follow the steps below to make your own cold storage room.

DIY Cold Storage Room


  • A spare room
  • Some blackout curtains or blinds
  • A portable air conditioning unit (preferably with both heating and cooling functionality)


  1. Install your blackout curtains or blinds on every window in the room.
  2. Plug in your portable A/C and plug it into a wall socket.
  3. Place the fermentor near the A/C unit.
  4. Turn on the A/C and adjust the setting to your desired temperatures.

DIY cold rooms can be inconsistent in maintaining temperature, as heat can be gained or lost to the outside environment.


4. Styrofoam Fermentation Chamber

In his YouTube channel, The Regular Chef demonstrates how to make a proofing box. While the box is designed for bread fermentation, you can repurpose it for brewing. Below is a list of equipment you’ll need for the project:

Styrofoam Fermentation Chamber


  • A styrofoam cooler (big enough to accommodate your fermentor)
  • Heating mat
  • Temperature controller


  1. Lay the heating mat on the bottom of the styrofoam cooling box
  2. Plug the heating mat into your temperature controller
  3. Insert the temperature probe inside the fermentor.
  4. Plug the temperature controller into a wall socket.

This styrofoam fermentation chamber is cheap and easy to make, but it lacks a cooling functionality. You can elect to pour in some ice during the warm months, but it won’t be as effective. For more information, check out the video below.

5. Cooler Bag

A cooler bag, due to its insulating properties, makes for an excellent fermentation chamber. It’s big enough to accommodate a regular-sized fermentor. It also protects your brew from photooxidation.

You can lower fermentation temperatures by dropping in a few bags of ice. To warm your fermentor, drop a few bags of warm water along with your fermentor.

Commercial Fermentation Chambers

Commercial fermentation chambers also double as fermentation vessels. They are sophisticated and riddled with the latest in modern technology. Below are fermentation chambers that are commercially available to brewers:

1. Stainless Steel Bucket Fermentor

Stainless Steel Bucket Fermentor

The bucket fermentor is a stainless steel fermentation vessel. It comes standard with an in-built racking system.

While it doesn’t have a heat exchange system, it is compatible with such attachments. Stainless steel bucket fermentors are made for homebrewers. Below are some of the advantages and disadvantages associated with these fermentors.


  • Easy to use
  • Accurate


  • Expensive to buy

The most popular example is Anvil’s bucket fermentor which comes with a capacity of 7.5 gallons.

2. Cylindroconical Tanks

Cylindroconical Tanks

Cylindroconical tanks are the most popular fermentors in the commercial brewing scene. They do an excellent job in temperature control and maintaining optimal fermentation conditions. Cylindroconical tanks are assembled from two shapes; a cylinder and a cone.

Cylindroconical tanks are made of stainless steel. They come in various sizes with different levels of technology.

The smallest and simplest examples are targeted at homebrewers. For example, this 7-gallon Crucible Conical Fermentor by Anvil or the X1 Uni conical Fermentor by BrewBuilt. Both options don’t come standard with heating or cooling systems. But they can be easily fitted with various heat exchangers.

The biggest and most sophisticated cylindroconical tanks are targeted at commercial brewers. They come in different brewing capacities (measured in barrels) with varying tech levels. You can expect sophisticated temperature control systems, pressure gauges, and racking systems.


  • Highly accurate temperature and pressure monitoring systems
  • Easy to clean
  • Increased brewing capacity


  • Expensive to buy

Factors to Consider When Choosing a Fermentation Chamber

Factors to Consider When Choosing a Fermentation Chamber

What makes a sound fermentation chamber? Well, different brewers will have different answers to this question. But you should consider these factors to find the best option for your situation:

  • Budget: Your budget will dictate the kind of fermentation chamber you buy. You may opt for DIY fermentation chambers if you’re a homebrewer with a tight budget. But if you have some money to spare, you can go for cylindroconical fermentation tanks.
  • Space: How much space do you have? You can only get a fermentation chamber that makes sense for your space. If you have a spare room, you can convert it to a cold storage chamber.
  • Insulation: Insulation is important because it helps the fermentation chamber keep heat. It also helps maintain temperature consistency and reduce the risk of fluctuation.

Temperature Control and Monitoring

A good fermentation chamber should allow you to manipulate and track temperature levels. Effective temperature control gadgets include thermostats, glycol chillers, and heat exchangers. Effective temperature monitoring systems include thermometers, temperature sensors, and probes.

Light Protection

Beer is sensitive to light, resulting in an effect called photooxidation. It ruins your beer’s flavor and aroma. Light exposure leads to beer skunking. This is a phenomenon where the beverage develops a funky smell. The ideal fermentation chamber must offer light protection.


The primary role of fermentation chambers is temperature control. But they also help with light protection and flavor preservation. A fermentation chamber is an essential brewing tool. Your budget and space will dictate the kind of appliance you buy. Don’t take chances with your fermentation process; invest in a proper fermentation chamber.

The Ultimate Guide to Fermentation Chamber

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