What You Need To Know About Beer Homebrewing Airlocks

home brewing air lock

Homebrewing is now a trend for beer drinkers since craft beer prices are now increasing. It can be a fulfilling activity to learn how to produce your beer and it will ensure that you will never run out of supply of cold beers.

To start homebrewing, specific base ingredients are needed such as malt, hops, and yeast. Special homebrewing equipment is also needed to get the exact brewing procedure in producing quality beer. Basic home brewing kits are available in the market for beginners and additional equipment may also be used once you become an expert in brewing.

Getting the right equipment will help you in easy brewing. These supplies include a large pot that can hold up to 5 gallons and a large container with a small hole for the airlock which will aid the fermentation process. Having control over the fermentation is an essential part of homebrewing since it will determine the taste of your beer. For this article, we will talk about airlocks – types, importance, and some processes.

What is an Airlock?

An airlock is a piece of equipment that plays a vital role in the fermentation process without spending a fortune. Its primary purpose is to let carbon dioxide come out during the process while ensuring that bacteria and oxygen will not enter the fermentation which may contaminate the process.

The airlock is mounted on the tip of the container through a rubber bung. This piece of equipment is necessary for keeping the brewing seal sterile and preventing the container from exploding since it lets the carbon dioxide come out during the process.

Why Is An Airlock Needed For Brewing Beer?

As bubbles rise during the fermentation process, carbon dioxide helps in increasing the pressure in the container. All fermenting containers have a limit on the pressure they can take. If it cannot withstand the pressure, its lid may pop out which will allow bacteria and dust to enter the fermentation and may eventually lead to spoilage of the beer.

With the use of an airlock, it finishes the fermentation process – allowing the carbon dioxide to escape to prevent pressure without letting the oxygen come inside the container.

These are made with a plastic material to let the brewer observe the process and ensure that no contaminants have entered the airlock.

Types of Airlocks

There are 2 basic styles of airlocks that can be used for brewing. But these types share the same goal – to prevent pressure build-up during the fermentation process.

The first type of airlock is the S-shaped. It is a single-piece plastic and is one of the primary designs of an airlock for brewing and is preferred by most homebrewers. It is filled with water to create bubbles from the gas coming out of the fermentation process. With its clear material, you will be able to determine if the fermentation process is ending.

The only downside of using an S-shaped airlock is that debris from over-fermenting can be difficult to clean due to the curves.

Another type of airlock is the 3-piece airlock. Compared to the S-shaped, it is a modern design consisting of a base, piston, and a vent cap. The base will be filled with water where bubbles will rise during the fermentation process as it releases the carbon dioxide.

It is easy to clean since it can be dismantled.

How Much Water Should I Put in a Homebrew Airlock

Enough amount of water serves as a barrier between the gas produced during the fermentation process and outside air.

For an S-shaped airlock, the ideal amount of water is ⅓ or almost half of each chamber. Once you fill one chamber with sterilized water, it should be tilted to fill up the other chamber through the bends. Most of the S-shaped airlocks have an indicator of how much water you should fill.

For the 3-piece airlock, identifying how much water should be filled is easy since it has an indicator of how much you should fill.

Some brewers do not use sterilized water. Instead, they use a food-grade sanitizer or alcohol such as vodka. It is recommended not to use tap water since it may already contain bacteria and other contaminants and may spoil the whole batch of beer.

Regular checking of the water level is necessary to see if there is dust or anything that has entered the airlock. Additional water may be needed especially if the weather is warm as it may add up to the evaporation of water from the airlock.

How Much Should My Airlock Bubble

Airlocks produce bubbles which determines that the fermentation process is ongoing. Beginners usually think that once the bubbling stops, the fermentation ends. The process may last for days. If it is not bubbling and you just started the fermentation process, it may indicate that the lid is not fully sealed or there may be another opening in the container where the carbon dioxide comes out.

The fermenting process can be determined if successful once bubbles appear actively during the first 5 days. Typically, the fermentation process is completed within 7 days. Once the bubbling slows down, it may indicate that the fermentation is about to be completed. The produced bubbles will only determine that the fermentation process is ongoing, but using a hydrometer will let you have accurate monitoring of the fermentation process.

Even after the fermentation has stopped, airlocks still produce bubbles because the yeast started fermenting again. Fermenting buckets are not recommended to be opened for at least 2 days after the bubbling stops. However, if you are using a transparent container, bubbles should be visible on the surface of the produced beer before they can be transferred to a bottle.

Final Thoughts

Investing in proper home brewing equipment is necessary to produce a quality beer at home. The use of the airlocks does not necessarily determine the ending of the fermentation process, it is still important to take a sample to taste the homebrewed beer or use a hydrometer to properly monitor the fermentation process.


Dan Specht

Dan has been homebrewing beer for 8 years and holds a level 2 certifiication as a Cicerone.

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