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Under Pressure- Burping your Ferments!

Using Airlock Systems to Release Built-Up Carbon Dioxide

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by Jody Gowans in Fermentation Tools, The Basics
April 3, 2017

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 it’s 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.  

GASSY BACTERIA!

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.   

MANUAL BURPING

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!

UNDER PRESSURE- RELIEVING EXCESS CO2 WITH AIRLOCKS

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.

1. 3-PIECE AIRLOCK (CUP AIRLOCK)

 

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

 Tools

  • Drill
  • ¾” 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.

    img_1398

    rubber stopper in drilled hole

  5. Insert the airlock into the rubber stopper

    img_1387

    airlock into rubber stopper

2. PICKLE PIPES

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 www.masontops.com.pickle-pipes

 

8 Comments
  1. Xeska says:

    Hola, interesante y gran artículo, estoy buscando fermentar miel para elaborar mead (hidromiel) pero es difícil de conseguir levaduras comerciales, algún consejo de como fermentar sin levaduras adicionales? Muchas gracias, saludos desde Oaxaca México

    1. Jody Gowans says:

      Hola! Sorry, I don’t make mead/hidromeil, but from my research you do need levaduras champagne or wine

  2. Will says:

    Do you know if the Nourished essentials fermentation kit is a reliable kit for self burping and just an overall kit

    1. Jody Gowans says:

      Thanks for the tip!

  3. Ankita A Patil says:

    Hello! Thank you for this article, it was really helpful! I’m trying to ferment ginger and garlic without a brine. I have the items in an airtight jar but it’s only filled halfway. Is this ok, or will the air remaining in the jar cause a problem? I don’t have an air lock so I was planning to manually burp the ferment every 2 days.

    1. Jody Gowans says:

      Hi Ankita- thank you for your interest and question. Just so I understand, you have just garlic and ginger in a jar with nothing else? This might be a problem if there is no salt or some sort of liquid used. You might want to double-check your recipe. To protect the ginger and garlic from pathogens (mould, etc), it is important that the garlic and ginger remain in an acidic environment (in a brine, or in a honey ferment). The headspace you mentioned (the jar is only filled up halfway) is not a problem- manually burping is fine to release the built-up carbon dioxide that will soon displace the oxygen in the jar.

  4. Marcele E Grote says:

    So I love my fizzy, fermented drinks, i.e. kombucha, kefir, kefir whey soda, etc. . . I am trying to find the difference between the CO2 from naturally fermented drinks and the CO2 from soda pop. Other than the obvious that soda’s have so many unhealthy additives . . . . . .

    1. Jody Gowans says:

      Hi Marcele- thanks for your interest and question! The CO2 in soda drinks is derived from forced carbonation (CO2 is pumped into the drink.) In homemade fermented drinks, the CO2 comes from the living microbes in the drink. During a process called second fermentation, the fermentation container is sealed, trapping the CO2 being transmitted from the microbes in the fermented drink. This is not true for most commercial fermented beverages, as the companies generally use forced carbonation to avoid any possible amount of alcohol that might be minimally produced during second fermentation. It is also easier for them to control the fizz by forced carbonation in large scale production.

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