Under Pressure- Burping your Ferments!

Lacto-fermentation is a fascinating transformative process.  Using the variables of salt, time and liquid, food is not only be preserved but transformed into a more nutritious and delicious version of its original self.  It is a fairly simple process to set up, with only a few factors to maintain.  Essentially, the fermenting food has to be kept under a brine and in an oxygen-free environment.


This acidic and anaerobic environment is inhospitable to pathogens that could ruin the ferment or make us sick.  It is ideal for beneficial bacteria, who thrive and happily munch away at the sugars in the food, basically predigesting it for us, allowing us to eat the food without any “gastrointestinal distress”.  The bacteria are not so lucky and produce a lot of carbon dioxide.  This gas has to be released without introducing oxygen into the fermentation container.


The easiest method to keep the food submerged and oxygen-free is to pack in or down the food so it will not float above the brine level, and to seal the fermentation container.  To release built-up CO2 from the container, you can loosen or slightly release the lid every few days. However, there are times when you just have too many simultaneous ferments to tend to.  Luckily, there are easy tools available to take over the babysitting duties of burping your ferments!


There are many products on the market that slowly release built-up CO2 from ferments.  While effective, they can be pricey if you have multiple fermentation projects.  I will share with you my top 2 airlock tools that I have had lots of success with.


3 -Piece Airlock

This is my favourite airlock that I use for my mason jar ferments.  They are easy to find online (Amazon) and readily available at your local wine/beer-making supply store.  They come in a variety of sizes and are inexpensive.

How a 3-Piece Airlock Works

3-Piece Airlock System- Cylinder with stem, cup and lid + rubber stopper
3-Piece Airlock System- Cylinder with stem, cup and lid + rubber stopper

Brine, filtered water or vodka is poured into the cylinder to the indicated waterline.  img_1385Built-up carbon dioxide escapes from the sealed container through the stem of the airlock.  It travels into the water and up the sides, escaping through the tiny holes in the lid of the airlock.  Oxygen, being a lighter gas, is prevented entry into the ferment as it cannot penetrate through the water barrier in the airlock and the escaping built-up CO2.

How to Make a Mason Jar Airlock System


  • Drill
  • ?” spade drill bit
  • plastic lid for glass canning jar
  • Rubber stopper
  • 3-Piece Airlock
  1. Screw lid onto jar (It helps to hold the lid steady while drilling if you don’t have a vice)
  2. Slowly drill a hole in the centre of the lid.  Be patient and don’t try and force the drill bit.

    Drill a hole in the centre of the lid
    Drill a hole in the centre of the lid
  3. Once the hole is created, smooth the edges on the underside of the lid with sandpaper or a file.
  4. Insert rubber stopper snugly into the hole.

    rubber stopper in drilled hole
  5. Insert the airlock into the rubber stopper

    airlock into rubber stopper


Pickle pipes are silicone inserts for mason jar lids.  They function as a one-way valve, similar to the nipple on a baby bottle.  The self-closing valve prevents oxygen from entering the ferment and allows for the escape of built-up carbon dioxide.

Fermented Chili pepper with Pickle Pipe
Fermented Chili pepper with Pickle Pipe

Pickle pipes generally come in sets of 4 and can be easily washed and reused.  I have 2 sets and use them for my mason jar ferments.  They can be purchased on Amazon or at

Share this post