Fermentation Facts Series – Installment #1


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Welcome to my Fermentation Facts Series. Two Fridays per month, I will address questions from you, my readers, as it relates to the basics of fermenting vegetables (and some fruits). Down the road I will tackle topics related to fermented beverages but for now, let’s keep it simple and not terribly overwhelming.

Why am I starting this series?

Did you read “Are You A Fermentation Floozy?” If not, head over to that post and give it a minute of your time. I’ll wait…

Good! You are back! So now you understand that when it comes to something as serious as the dangers of improper fermentation practices, you can bet your arse that I am going to choose how I ferment foods based on scientific research and evidence.  I will NOT follow fermentation guidelines and recommendations that are based on opinions, haphazard personal experiences, “generational knowledge,” word-of-mouth, or sponsor supported products.  

I don’t know about you but I want easy to understand information that can be backed with scientific evidence. While there are a sprinkling of posts out there like this, they seem to be the ones under attack the most. I just do not get that. You guard your health right? So why throw caution to the wind when it comes to something as delicate and powerful as lacto-fermented foods? Why trust word-of-mouth over research?

I have been inundated with some pretty basic questions regarding proper fermentation. I will do my best to give you a summary of what I have learned and how my own practices are changing in light of this information. Once again, my goal here is to break down some of the basics so that you can have the information you need to make a decision that you can live with when it comes to how best to ferment your foods.

At the end of each post in this series, I will provide you with information on the books, studies, and other posts that I used as part of my research. So I don’t get accused of product promotion, NONE of these will be hyperlinked! This way, you can trust that the information I am providing is not making me any money! It is unbiased.

I encourage you to continue doing your own research. Although I am confident in what I am presenting, it is ultimately up to you to make sure YOU have all the information YOU need. Of course, feel free to ask my anything! I will answer it in the comments or save if for a future post.

Question #1
What is anaerobic fermentation?

Anaerobic fermentation is the method used to keep oxygen from getting inside your vessel as well as allowing oxygen already present to escape. In lacto-fermentation, this is hugely important! An airtight environment protects the lactic acid bacteria (LABs) that occur naturally on the vegetables you use in your ferments. It also keeps harmful organisms out. LABs are not the only beneficial part of a properly fermented vegetable, but they are an important probiotic and the main healthful feature of fermented foods.

LABs do not like to share their space or their food source. If you have a vessel which allows oxygen in, the LABs have to compete with other organisms. They typically won’t do it. If you want the LABs to multiply and populate your ferments with all of their goodness, then you MUST have an anaerobic environment.

This isn’t the end of the story though. In addition to keeping oxygen out, you need to provide a way for the carbon dioxide that builds up in your vessel to escape. Bacteria produce a lot of carbon dioxide as they grow and thrive. This is a good thing as it gives your ferments that pleasing fizziness but you don’t want it to build up in your vessel. You need that carbon dioxide to push the oxygen that is present in your vessel up and then out of the vessel. In addition, too much carbon dioxide could lead to an exploding jar. True anaerobic fermentation properly handles oxygen AND carbon dioxide.

Question #2
Are there any ferments that DO need oxygen present?

Yes! Aerobic fermentation is the method used to ferment many beverages like kombucha, beer, and wine as well as apple cider vinegar. These ferments need oxygen present in order to develop the correct ph and the best flavors.But just to confuse you further, these ferments are actually BOTH aerobic and anaerobic. That is another post!

Question #3
Is the Pickl-It honestly the ONLY vessel that produces an anaerobic environment?

No it is not. The Harsh crock also produces an anaerobic environment. I have never used a crock personally (too big and clunky). I have only used mason jars (before I learned about Pickl-It) and for the past two years, my Pickl-Its. I cannot speak to the success of using a crock although the science supports it as an anaerobic vessel.

Here is how the Pickl-It works:
The Pickl-It’s glass lid with the wire-bail/airlock combination locks out oxygen’s entry, as well as releases oxygen from the fermenting chamber, pushed by carbon dioxide, out through the airlock.

Here is how the Harsch Crock works:
The crocks have weighted stones to submerge the food below the brine. A water gutter allows fermenting gases to escape but prevents outside air from getting in.

Question #4
Why won’t other set ups work? Many products state that they are anaerobic.

In order to get truly anaerobic conditions you have to have glass or ceramic jars AND lids, because they are both strong enough to withstand the pressure from fermentation gasses.

The mechanism to hold the lid onto the body must exert enough pressure or be heavy enough to prevent gas and brine from escaping from in-between. It must be a wire-bail and not a threaded closure as the threaded closures do not exert enough pressure to make it airtight.

The plastic lids and airlock systems used in other set ups offered can warp under pressure, enough to let out brine or let in oxygen.

Mason jars are only airtight once you have canned in them.  The airtight nature comes not from the threads holding the lid onto the lip of the jar but from the heat processing.  It is impossible to achieve an airtight lock in a mason jar without heat. (KerryAnn from Cooking Traditional Foods explains this in depth here).

I realize that my responses are incredibly short. But I wanted to get straight to the point. Again, this is simply a jumping off point for you to do further research.

Stay tuned for the next installment of my Fermentation Facts Series. I will be tackling the fermentation process as well as what you want and don’t want in your ferments.  Future posts will address the importance of a proper brine, how long to ferment your vegetables, what type of water to use when fermenting, how to clean your vessel, topping a ferment with oil, and the dangers of making your own “Pickl-It”. I will be sure to link to other great posts on these same topics as well!

As discussed, here are the sources I am drawing from for this series:

  • Applications of Biotechnology in Traditional Fermented Foods from the The National Academies Press
  • Fermented Fruits and Vegetables, A Global Perspective by Mike Battcock and Dr. Sue Azam-Ali
  • Handbook of Fermented Functional Foods, Edited by Edward R. Farnworth
  • Genera of Lactic Acid Bacteria by Brian J. B. Wood and W. H. Holzapfel
  • The Permaculture Book of Ferment & Human Nutrition by Bill Mollison.
  • The Potential For Upgrading Traditional Fermented Foods Through Biotechnology by O.K. Achi
  • Pickl-It website
  • Cooking Traditional Foods website


  1. I was looking for the rest of this series but can not find it. Can you help? Thanks

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