Watching a bubbling airlock during active fermentation is one of the most exciting parts of being a homebrewer but you might be wondering which airlock type is the best and which one you should be using to ferment your beer.
Any S-shaped airlock or 3-piece airlock works well for fermenting homebrew as long as it is properly sanitized, creates a tight seal with the fermenting vessel, and stays filled with sanitizing solution. Blow-off tubes can be utilized during active fermentation to avoid blowouts and then switched to either an S-shaped or 3-piece airlock later.
At the end of the day, nearly any airlock will work best as long as everything else is taken care of with the brewing process. Let’s take a look at the options available.
Overall best airlock for fermenting homebrew beer
I’ve used lots of different airlock types and styles over the years and, really, any airlock will work great as long as it is used properly. With that said, I do still have a preference.
Based on my experience, the best airlock for fermenting homebrew beer is a standard 3-piece airlock coupled with a blow-off cap and a blow-off tube. This setup takes care of both active fermentation as well as long-term fermentation safely.
When it comes to brand or manufacturer, most of these 3-piece airlocks are really the same – three plastic pieces that fit together and are then inserted in a bung to seal up a fermenting vessel.
Here is the list of items I would recommend if you are using a standard carboy that will get you through many homebrew batches in the years to come!
Using this setup, you’ll simply wrap the top of your carboy with the blow-off cap, install the 3-piece airlock in one opening and add a piece of 1/2″ vinyl tubing to the other opening. Once active fermentation subsides, just remove the blow-off tubing and cap off the opening.
The different types of homebrew airlock
Although I find myself using the 3-piece style of airlock most often, there are other options that will work just as well and you might even find that you prefer one type over another.
Since these items are fairly cheap, I would also recommend picking up one of each style and testing it out to see which you prefer. Worst case, you are out a few bucks.
Here is a good list to get you started:
3-piece airlocks get their name because, well, they have three pieces.
The main piece of these airlocks is inserted into the bung on top of the fermenting vessel. After adding a little sanitizing solution, you’ll place a small cup upside down over the open to the main piece to create the air gap between the outside air and the inside air. Finally, a cap is added to the top to make sure nothing falls into the airlock.
As long as the pieces are put together properly and the airlock is kept partially filled with sanitizing solution, a 3-piece airlock will work great during fermentation.
Of course, a 3-piece airlock does have a tendency to run into trouble during very active fermentations. If your fermenter is filling up with foam and yeast material to the point where it reaches the airlock, it will quickly get clogged and you’ll risk having a blowout and quite a mess.
We’ll discuss this down in the blow-off section, but it’s usually a good idea to start things off with a blow-off tube and switch to the 3-piece after fermentation slows down a little.
The other most common type of airlock is the s-shaped or ‘twin bubble’ style of airlock.
S-shaped airlocks are made of one piece of plastic along with a small cap at the top which makes them easier to keep track of and the twin bubbles allow them to hold more sanitizer so you won’t have to worry as much as about them going dry during fermentation.
Unfortunately, s-shaped airlocks are much more difficult to clean compared to 3-piece airlocks because you can’t take them apart and the twisty bends of the s-shape means you’ll need a special cleaning wand to brush them out if they get yeast blown up into them.
With that said, I’ve used s-shaped airlocks in the past and, other than the cleaning annoyance, they work quite well!
Tubing or blow-off airlocks
While not suitable for long-term fermentation, blow-off tubes and other alternative airlocks can serve a useful purpose during active fermentation.
Blow-off airlocks normally use large tubing to allow more gas to escape during active fermentation and can even allow solid material such as yeast to exit the fermenter that would normally clog a traditional airlock. Once active fermentation has slowed, however, the lack of a sanitized air gap means that blow-off airlocks would allow bacteria to enter the fermentation vessel.
To get the best of both worlds, I recommend getting a blow-off hood with individual caps that will allow you to use a blow-off tube and traditional airlock at the same time.
The list of products in the first section above will get you started!
Can I ferment without an airlock?
Many homebrewers wonder if they can get away with fermenting their batch of beer without using a fermenter either because they want to save money or they have misplaced/broken their airlock and they are panicking after the beer is already inside the fermenting vessel.
It is usually a bad idea to ferment beer without an airlock because it will allow bacteria to enter the fermenter and potentially infect the beer inside. As with everything in homebrew, sanitation is key and it makes no sense to risk an entire batch just to save a few bucks.
With that said, if you find yourself in a situation where you simply don’t have an airlock to use there are a few things you can do:
- Wrap a balloon over the top of the carboy and poke a small hole in the top. This will allow air to escape when pressure builds inside the balloon but will minimize the amount of air that will make it inside.
- Plastic bag rubber-banded to the top of the carboy with a small hole poked in the top.
- Aluminum foil tightly wrapped around the opening to the carboy.
In all cases, be sure to thoroughly sanitize whatever you use to cover the carboy to avoid contamination.
I’ve also covered this topic in more detail in this post here if you want to learn more.