How to Choose a Beer Fermenter: Complete Guide!

Fermentors, which generally are called fermenters, are an absolutely essential piece of equipment when it comes to brewing beer since they can have a direct impact on how your beer turns out. But with so many different ones to choose from, from plastic bucket fermenters, glass & plastic carboys, to stainless steel fermenters, which one should you choose?

In this article, we are going to delve into the world of fermenters, more specifically on what we need to take into consideration when choosing the one that best meets our needs and requirements, both in terms of the material it is made of and the price.

So: How to choose a fermenter? To choose a fermenter you have to take into account two factors: the quality of the material it is made of, as they can be made of plastic, glass, or stainless steel, which affects its durability, among other things, and the price, because depending on the material, the valves it has, if it comes with temperature control, pumps, etc., all of this will affect the final price.

Obviously, not all brewers will benefit in the same way from each type of fermenter, since the fermenter that will be used by someone who produces beer on a medium to large scale is very different from the one that someone uses to produce beer once a month at home as a hobby.

First, let’s look at what a fermenter is and what it is used for, and then we will go into detail on each type of fermentation vessel there is, the different materials you can choose from, their overall features, shapes (conical fermenters), etc.

What is a fermenter?

A fermenter is a vessel in which, in the case of beer, the cold wort meets the yeast to carry out fermentation and, in many cases, it is also used for the maturation of the beer.

Typical Bucket fermenter used for the Brewing Process.

There are several types of fermenters, both in size, shape, the material they are made of, and defining characteristics (whether they have taps or not, etc.).

Types of fermenters

  • Fermentation Bucket: these are cylindrical plastic containers made of PET (similar to paint plastic buckets) and are the most popular option for beginners due to their low cost, both for the fermenter as well as its maintenance.
  • Glass Carboy: Glass Carboys are excellent for fermenting beer since they are easy to clean, allow you to see what is going on during fermentation, and are quite affordable, especially when you consider that they can last a lifetime if well cared for.
  • Plastic Carboy: Plastic Carboys are one of the favorite fermenters homebrewers use since they are made out of cheap PET plastic but also share the same shape as the glass Carboy and are easy to obtain as well as very cheap.
  • Stainless Steel: This material is the most expensive one so far, but at the same time it guarantees a healthy fermentation thanks to its design and construction material.
  • Conical Fermenter: (Plastic and Stainless Steel): They differ from the other fermenters on this list basically because of their conical base, which allows for optimal flocculation of the yeast for its subsequent purging or harvesting.
  • Demijohn: Demijohn fermenters have the same characteristics as glass carboys but with the advantage that they are generally made out of dark glass, which keeps UV light from reaching the beer and prevents a loss in beer quality. Additionally, they come in a protective woven basket that protects them from getting damaged.
  • Speidel: Designed in Germany specifically for beer fermentation, a Speidel fermenter is made out of high-density polyethylene, which makes it highly resistant to scratches (this prevents the buildup of bacteria and therefore can keep fermenting beer from getting infected).

What Fermenters do we usually use at home?

I would always advise new homebrewing enthusiasts to go with the simplest and cheapest option available, which would either be a fermentation bucket or a normal plastic carboy, although glass carboys can also be found quite cheap if you know where to look.

Then, as you learn more about homebrewing and you know that this is a hobby that you’ll stick with in the long run, you can start investing in higher-quality fermenters, maybe getting a Speidel or conical fermenter at first and then moving up to stainless steel.

Fermentation Bucket

Plastic Fermentation Bucket.

Plastic fermenters are the most used and economical fermenters that exist in the homebrew world, and bucket-style fermenters are definitely the cheapest and most conveniently sized fermenters out there.

These containers are usually white and have a lid on the top with a hole for the airlock. Some may even have a tap on the bottom for sampling, bottling, or for making cleaning and emptying the fermenter easier (truth be told, most have a tap which makes them very handy).


  • Very low cost.
  • Shock resistant.
  • Lightweight and easy to transport.


  • Very sensitive to scratches which can lead to subsequent contamination of our beer due to bacteria accumulation in those scratches.
  • Lower durability compared to other fermenters.
  • Low capacity (generally about 30 liters, or 6 gallons, maximum).
  • The plastic material can affect and modify the flavor of the beer.

Carboy (Glass)

Glass Carboys with Blowoff Tube and Airclocks.

These are big glass bottles originally designed for transporting and storing liquids and are among the most popular fermenters because of their high quality, they are easy to clean, and they allow you to see what is happening during fermentation.

I believe that the reason that people love them so much is that since they are glass fermenters, you can see the fermentation in action and also tell when something is going wrong (beer infection, stalled fermentation process, etc.).


  • Inexpensive and easy to get. You may even have one in your home without even knowing.
  • Scratch-resistant material.
  • Impermeable to oxygen (very important since this is one of the biggest enemies of beer after the main fermentation is completed).
  • Suitable for extended cellaring and aged styles.


  • Not very resistant to impacts.
  • Less resistance to the positive pressure that may be generated by our fermentation gases.
  • Generally more expensive than plastic.
  • It has a narrow hole, which makes it difficult to clean or to add fruit or hops to our beer.
  • They do not have taps that allow us to take samples.

Carboy (Plastic)

High-quality Plastic Carboys.

These are just normal plastic carboys that have the same shape as the glass ones I just mentioned and are generally used for transporting and storing liquids, most commonly water (the big water jugs you can buy for your home).

Plastic Carboys are also widely used for fermenting brew since they are quite shock-resistant, relatively easy to clean, and transparent which, while not good for the beer itself, allows us to see what is going on (keep them in the dark).


  • Low cost.
  • Easily available
  • Lighter and more shock-resistant compared to glass ones.


  • Because they are transparent they let light through which is extremely detrimental to beer, especially hoppy styles.
  • Easily scratched which can lead to contamination.

Stainless steel Fermenters

Stainless Steel Fermenter.

The steel used for these kinds of fermenters is the so-called 304 food-grade stainless steel, and these fermenters can be cylindrical or conical.

Stainless steel fermenters, mainly because of their robustness as well as high price tag, tend to be used mostly at large-scale breweries and not so much by home brewing enthusiasts.


  • Great resistance to all kinds of stress, whether they are shocks, scratches, etc.
  • They can withstand high levels of pressure which means that maturation and carbonation can be carried out in them.
  • Easy to clean thanks to the possibility of using pumps and caustic soda-based products at high temperatures.


  • In the case of cylinders, it is not possible to separate the sediment from the liquid at the bottom of the tank, leading to possible losses.
  • Their cost is significantly higher compared to the other options.
  • They require additional equipment to be able to be used properly (pumps, cooling systems, hoses, etc.).
  • Difficult to find them in sizes suitable for home production.

Conical Fermenter (Plastic and Steel)

Plastic Conical Fermenter.

These are, bar none, the best option when it comes to microbreweries since they have a large number of features that facilitate most of the processes that need to be carried out during and after fermentation (yeast harvesting, dry-hopping, additions of fruit and spices, etc.).

As for their physiognomy, they have a cylindrical top that ends in a conical base and they generally have valves and taps on the top, front and bottom.

They may also have doors at the front, called Manholes, which serve as a way to inspect the tank from the inside (this is mainly the case with big large-scale conical fermenters).


  • Easy to clean.
  • Greater security in terms of the quality of our product.
  • Better yeast flocculation.
  • Possibility to perform a yeast harvest.


  • High cost compared to those mentioned above.
  • Requires more available space.
  • Difficult to transport.

Now that we have seen the different types of fermenters, we should talk about an important topic which is the Krausen, since with some types of fermenters, mainly glass and plastic Carboy ones, it can create some complications if the fermentation is too vigorous.

What is Krausen?

Two beers fermenting in glass Carboys.

Krausen is a light, creamy-colored foam composed of yeast and wort proteins that begins to form at the top of the beer during the primary fermentation process, and represents a healthy fermentation.

As fermentation begins to slow down, the Krausen also slowly subsides and the yeast settles at the bottom of the fermenter, which generally indicates that it is time to transfer the beer to a secondary fermenter.

Note: You should always take gravity readings to determine whether or not fermentation is complete and don’t just focus on the Krausen.

Depending on the type of yeast strain that was used, as well as other factors, the Krausen generated can get very high and cause our fermenter to overflow.

Problems with using a Carboy for fermentation

Overflown Airlock.

The biggest problem with this type of fermenter is that the reverse funnel-shaped top is prone to overflowing due to the reduction of headspace available in carboys. In addition to this, the narrow diameter of its opening increases this risk.

Once the fermenter overflows, the airlock might seal up completely and cause a lot of CO2 to build up inside the fermenter, and if there’s enough pressure built up, then we might have an issue!

If you’ve ever seen an exploding glass carboy then you know that it’s not a pretty sight. Not only can it be dangerous but it’s also a mess to clean up!

This leads us to think about the type of system we should use to allow CO2 to escape since we cannot leave the fermenter completely uncovered since we need to prevent contamination and oxidation.

So, here we have two options:

Airlock vs a BlowOff Tube

Image Source: How to Brew.
Image Source: How to Brew.

Airlock: An Airlock is a device created to allow the release of gases without allowing anything from the outside to enter the container, which is why it’s always used when making beer.

Its main advantages are its small size and low cost.

Some of its disadvantages are:

  • They overflow easily when the fermentation is too vigorous.
  • In the event of clogging, they can cease to perform their function, causing excessive pressure build-up inside the vessel.

Blowoff Tube: this is simply a tool to aid the release of the carbon dioxide produced by our beer through a hose that flows into another container containing water or sanitizing liquid.

This method has the advantage that it is difficult for the whole system to clog up.

Which one do I recommend using?

After explaining in detail each of the options currently available on the market and focusing mainly on fermentors aimed specifically at homebrewers, my recommendation is based on the price-quality ratio.

The best option, in this case, I believe, is the plastic conical fermenter.

There are many conical fermenter options available today and in terms of price, they are quite affordable. Their greatest virtue is that they can achieve the same result as a steel one for a fraction of the cost, and you just have to take some extra precautions so that they can last for a few years.

Unlike the more basic containers, these greatly reduce possible contamination and oxidation during maturation and allow for proper yeast flocculation and harvesting.


Fermentation is the most important part of beer brewing, whether at home or on an industrial scale. During this stage, contamination must be avoided at all costs, so make sure to sanitize all of the equipment properly.

If you’re someone who is just starting out, there’s no need to go for an expensive stainless steel or conical fermenter since you can definitely get by with a $5 plastic bucket and then you simply upgrade later down the line.

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