The Top 5 Fermentation Chambers

If the goal is to brew the best quality beer possible then after the purchase of your brewing equipment the next consideration might want to be given to a fermentation chamber. Maintaining the correct fermentation temperature and reducing the exposure to light are of the utmost importance when making beer as temperature and UV rays have a direct impact on the quality of the beer.

In this post, we are going to discuss whether your unique brewing needs require one, what a fermentation chamber is, and the different options you have for building or securing one for yourself.

Do I Need a Fermentation Chamber?

The answer is it depends.

The first thing it depends on is how concerned you are with the quality of the beer you are brewing. Many homebrewers are content to just brew a decent tasting beer, one that would compare or even be superior to the commercial beers the big-name breweries make.

If that is your goal it can be easily achieved by placing your fermenter in an area in your home that will maintain temperatures in the range of 60 – 75℉. If the temperature fluctuates within this range during fermentation you need not be overly concerned.

For us, at Make Beer Easy if we are simply brewing a beer for our own use and are not looking to sell it or win a competition we do not get overly concerned if temperatures creep up towards 80℉.

However, if you are looking to brew a top-quality craft beer that would rival any that your local microbreweries serve then you are going to require a fermentation chamber. Because the fact is that when making that quality of beer, fermentation temperature control is crucial.

Fermentation Temperature Control

There are studies and experiments that compare the difference between the same recipe being brewed at 65℉ and another at 75℉. At the higher end of the temperature range, you will notice an increase in many of the off-flavors, most of them will not be to levels that are intolerable, however, the infamous green apple off-flavor caused by acetaldehyde that many people associate with a homebrewed beer can increase substantially, some reports indicate it can increase up to 19 times higher.

One of the keys to a successful fermentation that results in no off-flavors being created is understanding the strain of yeast you are brewing with. Most packets of yeasts will indicate the full temperature range you can ferment at, but they will also indicate the ideal range. You want to keep within the ideal range if you are concerned about producing the best results.

Another thing to keep in mind is that fermentation itself generates heat within the fermenter. A 5-gallon batch of beer fermenting can generate 5 – 10 ℉ of heat within the fermenter. So if you are keeping the room you are fermenting in at the higher end of the temperature range i.e. 75℉ your beer could, in reality, be fermenting at 85℉ resulting in many off-flavors being produced.

A fermentation chamber allows you to control and dial in the precise temperature you want to ferment at.

Controlling UV Exposure

Not only can sunlight increase the heat of your fermentation but it also can cause another off-flavor to develop as a result of a reaction called lightstruck.

Lightstruck is when the beer is exposed to UV rays causing a chemical reaction between the alpha acids in the hops, the riboflavin from the malt, and hydrogen sulfide. This reaction results in a skunky odor and flavor developing.

A good example of this occurring is in the commercial beers sold in clear and green bottles. The skunky flavor has developed as a result of the UV rays penetrating through these bottles and into the beer itself. The same thing can happen if UV rays are allowed to penetrate through a fermenter and into the beer.

What is a Fermentation Chamber 
Cooler as a fermentation chamber
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A fermentation chamber can be anything from an insulated bag, a modified cooler, or a fridge, to a dedicated space in your home and anything in between. It must be large enough to accommodate your fermenter and the equipment required to regulate the temperature.

The key to a good chamber is that it will provide you the ability to control the temperature levels, allowing you to maintain them at the temperature you desire while not permitting fluctuations from external sources. It will also not permit exposure to UV rays.

As you will see there are many options when it comes to determining the fermentation chamber that is right for your brewing needs…

DIY Fermentation Chamber

One thing to note is that pretty much every fermentation chamber for homebrewing is a DIY job. Some are simpler than others, but really none of them on this list are overly difficult to build and anyone with some ingenuity can have one up and running for themselves in no time.

1) The Swamp Cooler

This DIY fermentation chamber is probably one of the most widely used chambers by brewers, simply because it is the simplest and least expensive chamber to get started with. The downside to it is that it does not run on autopilot and requires constant attention.

However, one thing to keep in mind is that most of the off-flavors that occur from temperature fluctuations occur within the first 72 hours, with that in mind you really only need to be concerned about dialing in your desired fermentation temperature for those 72 hours after that slight fluctuations will not affect the final product.

This setup is basically one step up from simply placing your fermenter in a dark and cooler location in your home. It consists of a large bucket filled with cold water in which you place your fermenter. Wrap a towel around the fermenter so the cold water wicks up the towel and keeps all of the fermenter cold and not just the lower part that is submerged in the water.

Place a stick-on thermometer on your fermenter in order to get an accurate temperature reading. Next, fill the bucket with ice packs. Take temperature readings every few hours to determine if you need to add more ice packs in order to keep the wort within your temperature range. If you need to really drop the temperature fast due to the area you are fermenting in being overly warm, you can use an electric fan pointed at the fermenter to help with cooling.

2) DIY Fermentation Chiller

There are many plans online for this style of DIY fermentation chiller. Although there have been many variations to this contraption the one that gets the most credit and recognition is called The Son of Fermentation Chiller and was originally designed by a fellow named Ken Schwartz.

The concept is similar in nature to the swamp chiller, however, it provides for better control over the temperature and does not require constant attention in order to maintain it at the temperatures you want.

Basically, it is a large cooler like structure that you build out of 2” insulation (foam board). It has a couple of chambers in it, a larger chamber where you place your fermenter and a smaller chamber referred to as the “ice chamber” that you fill with jugs filled with water that you have frozen.

There is a small fan situated between the two chambers that is controlled by a thermostat. As the temperature in the box becomes higher than the temperature you have set on the thermostat, the fan kicks on, blowing cool air from the ice chamber into the fermentation chamber. The fan stays on until your desired temperature is reached.

Here is a link to the original design. A couple of things with it. He recommends an indoor-outdoor thermometer from radio shack. We recommend you get an inkbird, they are a great thermostat that countless brewers around the globe use for heating and cooling, very reliable. For a fan they recommend what appears to be little computer fans, we have never been a fan of having to wire those up, and have found small desktop fans that plug into the inkbird work great also.

Other variations of this design use a mini fridge (small countertop bar type fridge) instead of the ice chamber. You build the cooler out of the 2” foam board, however instead of building two chambers you build one large fermentation chamber, you remove the door from the fridge and you connect the chamber directly to the fridge.

You then connect the thermostat (inkbird) to the fridge (it just plugs into it) and when the temperature needs to cool down the fridge kicks on. Which of course saves you from having to add jugs of ice. There are many youtube videos that show you exactly how to build variations of these styles of chambers.

3) Freezer or Fridge Fermentation Chamber

One of the more popular options for a fermentation chamber is using a refrigerator or a chest freezer.

It is a pretty simple process to turn either of these into a fermentation chamber. A basic one simply consists of a thermostat with a probe such as the inkbird. You plug your freezer into the inkbird and you place the probe into the freezer. You set the temperature you want the chamber to stay at and you are done. Simply place your fermenter into the cooler and let the thermostat handle the rest.

A trick we have found to help keep the temperature of the wort at the precise temperature you desire is to also put a container of water in the freezer, now put the temperature probe into the water. This way the thermostat is reading the temperature of the water which will be similar to the wort and not the temperature of the air in the freezer.

Another great thing about this setup is you can also use it as a kegerator to serve your beer from kegs.

4) Temperature Controlled Fermenters

If you are not interested in building your own fermentation chamber and are prepared to spend a little money then you may want to look at the temperature-controlled fermenters that are on the market.

They are a great piece of equipment that allows you to maintain your fermentation temperature to pretty much the exact degree. Most of them are controlled by a stainless steel coil within the fermenter, that is connected to a pump and a thermostat. When the temperature varies from what you have it set at the pump kicks on and pumps either ice water or glycol through the coil effectively bringing the temperature back into line. Although it will cost you a little more to get set up, the glycol chiller is superior to using ice water as you do not need to continually be adding more ice to the cooler.

This setup is very similar to what the craft breweries use and allows you to get greater control over your fermentation and the quality of your final product.

5) A Walk In Fermentation Chamber

If you really want to up your game you may want to consider building a walk-in fermentation chamber or cooler. Many small brewpubs use this type of setup for both fermentation and keeping their beer at serving temperature. Beer taps can be added to the exterior wall of these chambers and they can double as a keezer of sorts.

There are many plans online for these sorts of chambers. Basically, they consist of framing up a room and then using sheets of insulation as the walls and ceiling. An air conditioner connected to a temperature controller is used to cool the chamber. The temperature controller regulates the AC unit and allows it to drop the temperature down to refrigerator levels.

The Final Word

Depending on how determined you are to brew the perfect pint of beer you may or may not require a fermentation chamber. If you have a space in your home that you can keep dark and maintain temperatures within the ideal range as indicated on the yeast packet then a fermentation chamber is really not a necessity but an added bonus.

However, if the temperatures in your home exceed the ideal temperature range or even come close to doing so you will most likely need to rig up a fermentation chamber of some sort in order to prevent off-flavors from developing.

P.S. Be sure to grab the recipes for my top 5 best-selling beers from my brewpub. Details are on the side of the blog or at the bottom if you are on your smart device. Cheers!

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