Best Airlocks for Fermentation (3-Piece vs S-Type Explained)

If you're starting a batch of wine, one of the smallest pieces of equipment can make a surprisingly big difference: the airlock.

Airlocks help protect your wine during fermentation by allowing carbon dioxide to escape while keeping outside air, dust, and contaminants from getting in. But which style should you use - a 3-piece airlock or an S-type airlock?

In this guide, we’ll break down the differences, when to use each one, and which option may be best for your setup.

What Does an Airlock Do?

During fermentation, yeast converts sugar into alcohol and carbon dioxide (CO₂). That gas needs somewhere to go. An airlock creates a one-way barrier: CO₂ can bubble out, but outside air cannot easily get back in.

That helps reduce the risk of contamination and oxidation while your wine is actively fermenting.

3-Piece vs S-Type Airlock: What’s the Difference?

The two most common styles are the 3-piece airlock and the S-type airlock.

Both do the same basic job, but they differ in design, ease of cleaning, and how they perform during fermentation.

3-Piece Airlocks

A 3-piece airlock is made up of a main body, a floating inner piece, and a cap. It’s a very popular option because it is simple, effective, and easy to take apart for cleaning.

Advantages of a 3-piece airlock:

• Easy to disassemble and clean
• Simple design that is beginner-friendly
• Great for routine wine, beer, and cider fermentation
• Available in multi-packs for keeping extras on hand

If you want a standard, dependable option, a 3-piece cylindrical bubbler is a solid choice. If you ferment often, it can also make sense to keep a 2-pack or 3-pack around.

S-Type Airlocks

S-type airlocks have a curved, one-piece chamber design. Many winemakers like them because they are compact, simple to fill, and easy to monitor visually.

Advantages of an S-type airlock:

• Compact one-piece design
• Easy to see bubbling activity
• Good choice for standard fermentation setups
• Fewer loose parts to keep track of

If you prefer a streamlined design, the S-type airlock is a great option.

Which Airlock Is Better?

There isn’t one universal winner - it depends on what matters most to you.

• Choose a 3-piece airlock if you want easier cleaning and a classic all-purpose design
• Choose an S-type airlock if you want a compact one-piece style with simple day-to-day use

For most home winemakers, either style will work well as long as it fits properly and is filled correctly.

Airlock + Bung Combos: The Easiest Option

If you’re fermenting in a 1 gallon jug or a smaller carboy, an airlock with #6.5 bung can be one of the easiest solutions.

It saves you the trouble of matching parts separately and helps ensure you have a compatible setup right away.

Common Airlock Questions

Why is my airlock not bubbling?

That does not always mean fermentation has stopped. Sometimes the seal is not perfectly tight, or fermentation is moving slowly. Look for other signs as well, such as gravity readings or visible fermentation earlier in the process.

How much liquid should I put in an airlock?

Fill it to the recommended line using water or sanitizer solution. Overfilling can cause messes; underfilling reduces protection.

Do I need an airlock for wine fermentation?

If you want a safer, cleaner fermentation process, yes - an airlock is a standard and highly recommended part of a home winemaking setup.

Best Airlock Options for Home Winemakers

• 3-Piece Cylindrical Bubbler – dependable, easy to clean, and beginner-friendly
• S-Type Airlock – compact and simple one-piece design
• Airlock with #6.5 Bung – convenient combo for compatible jugs and carboys
• 3-Piece Airlock 2-Pack – handy for multiple batches or backup
• 3-Piece Airlock 3-Pack – great for winemakers who ferment regularly

Final Thoughts

Both 3-piece and S-type airlocks are proven options for fermentation. The best choice comes down to your preferred design, cleaning habits, and vessel setup.

If you want easy cleaning and flexibility, go with a 3-piece airlock. If you prefer a compact one-piece design, an S-type airlock is a great fit. And if you want a simple ready-to-use setup for smaller vessels, an airlock and bung combo is hard to beat.