Fermentation locks are commonly referred to as air locks. What these locks provide is a barrier to gasses outside of the fermentation container. There are two main types of fermentation locks that include dry fermentation locks and wet fermentation locks. Within these two categories, there are a few materials that are widely used including glass, ceramic, and plastics.

These fermenation locks offer a view into the activity of the fermentation process. For the wet fermentation locks, there is clear visibility into the gasses that are escaping. These gases will bubble the fluids as they escape. During peak fermentation bubbles will release at rates of up to 1 bubble every 1 or 2 seconds. The rate of gasses, however is not an indicator if the fermentation is going well or not....ie slower fermentation is fine. As the fermentation slows, so will the amount of cO2 production, thus escaping gases from the vessel and lock. The rate of escaping bubbles can slow to rates of a bubble every few hours or even days, so it is not a precise measurement. The yeast may still be highly active But it is a great indicator, and should be a good indicator for watching progress.

Without yeast starters, or if the temperature is not ideal for the yeast, the beginning of the fermentation cycle might be delayed slightly. Your fermentation fluids, and airlock may sit idol for days. Do not let this detour you from waiting it out, as there is something going on in there.

Wet Fermentation Locks

Wet Fermentation locks utilize water or fluids for creating a sealed barrier between the interior and exterior gasses. There are two main variations for shape which include an s-shape bubbler and 3-piece design. Both designs are attached to the carboy with the use of a cork or rubber stopper. As pressure of gasses within the fermentation vessel increase, the pressure forces the liquid in the fermentation lock outward. Based on the design, the fluids will swell around the pressure, and escape around the gas, letting out bubbles. If exterior pressure was greater than the inside pressure, the same would happen in reverse for the s-shape design.

There is some consideration of the type based on your container size and head room in the vessel. The s-shape design is more likely to clog with dried up sediment and fluids should the fermentation activity cause foaming in the container. The foam may reach the top of the container and enter into the lock. The s-shape design offers a smaller chamber, and this provides less room for circulation of the fluids. If a clog does form it could blow the lock off of the fermenter all together, allowing outside gases to enter. The s-shape is designed for smaller vessles that range from 1-5 gallons. If head room (gas above the fluid) is limited its better to go with the 3 piece design. This design has a wider chamber and will not clog as easily.

These devices range in price from very cheap to relatively cheap. The material itself should not be a concern as there should be no contact with the fermenting wort, or wine. This means that leaching of plastics is avoided and a non-issue. As long as the material is non-permeable and does not allow gases to enter the vessel, it will perform the task.

TypeMaterialPrice Range
S-Shape Fermentation LockPlastic (Unknown)$1.10 - $2.98
S-Shape Fermentation LockGlass$8.10 - $11.89
3-Piece Chamber Fermentation LockPlastic (Unknown)$0.99 - $3.10

  • Twin Bubble Airlock and Carboy Bung (Pack of 2)

    Product Features

    • Twin Bubble Airlock with Carboy Bung
    • Allows for slower evaporation
    • Universal Carboy Bung for 3, 5, 6 and 6.5 Gallon Glass Carboys


    • When filled with water allows Co2 gas to bubble out and prevents air from getting in. Enclosed design allows for slower evaporation from airlock bubble.
  • 3 Piece Airlock (Qty. 5)

    Product Features

    • Made of high-quality plastic
    • Used to maintain sanitary conditions for fermentations
    • 5 count


    • 3 piece airlock.
  • Pickle Lid - Maintenance Free Waterless Airlock Lids for Mason Jar Fermentation, Homemade Real Pickles, Sauerkraut, Kimchi. Mold Free, BPA Free - WIDE MOUTH, 3 LIDS, 1 PUMP

    Product Features

    • One-piece waterless airlock lid prevents mold developing on your ferment.
    • Automatically vent gas without air flow back into jar.
    • No need to burp the jar or fund water level every day.
    • Low profile design saves place. Can be stored in small place.
    • Fit any wide mouth mason jar. Can be reused for multiple times.


    • Turn a Mason jar into more with pickle lid

      Nowadays more and more people are rediscovering fermented foods either because they love the taste or because it's a good way to consume probiotics. But quality fermented foods are expensive, so making your own is a better choice. Fermentation vessel will be needed: fermentation crock works great, but take up place; airlock is difficult to store, clean and the water level has to be funded everyday. There should be a smarter solution! So this Pickle Lid was born. The one-way valve waterless airlock, which eliminates risk of mold , allows CO2 to escape while at the same time not letting O2 flow back into the jar; vacuum marker makes the sealing condition visible; date dial marks start date of every batch individually. Turn a Mason jar into a FERMENTATION JAR with Pickle Lid. A mason jar with this lid can creat a vacuum in the jar to keep your food fresh longer for 3 times. Turn a Mason jar into a VACUUM SEAL CONTAINER with Pickle Lid.

      Pickle making

      Pickle fermentation produced CO2. This pressure in the container must be released constantly or the jar may explode. Covering the jar with a cloth, or burp it every day, wiil expose the food to oxygen which cause harmful mold developing in your ferment. The Pickle Lid's one-way valve allows CO2 to flow through but blocks the O2 from returning back into the jar.

      Coffee storage

      The enemies of roasted coffee bean are moisture and air. Store your coffee away from them will keep it fresher longer. Therefore, an airtight container should be needed. The Pickle Lid can creat a vacuum in the jar, keep moisture and air out, lock flavor in.

      Easy to use

      The Pickle Lid is Absolute One-piece lid, no need to maintain or daily monitor, easy to clean (dishwasher safe), can be reused for years, and the low profile design saves place. It's multifunction is rewarding and cost-effective.

Dry Fermentation Locks

Dry fermentation locks are made with a movable ball or bearing that seals the container by gravity or force. When the there is equal pressure inside and outside of the vessel, the ball falls into place creating a seal. As the pressure inside the fermenter increases, the force displaces the bearing, allowing gases to escape. Once the pressure drops, the ball drops back into place creating a seal.

Dry fermentation locks alleviate the problem of evaporation that can happen in the wet fermentation locks. If enough fluids evaporate over time, this can eliminate the seal with the outside gases. With the dry lock this is obviously not a problem. Dry locks will fail if foaming is allowed to reach the lock from within the container. The sediment and evaporated fluids will prevent the lock from sealing.

Below is a table including the available locks on the market.

TypeMaterialPrice Range
Better Bottle Dry Trap Fermentation LockCeramic and Plastic (Unknown)$13.99-$14.95