Saturday, August 31, 2013

Fermentation Equipment, Part 1: Airlocks

When I'm fermenting vegetables and fruits, I often use a wide-mouth Mason jar. These jars have many virtues:
  • cheap
  • tough
  • available in a variety of sizes
  • easy to clean, dishwasher-safe
  • fit nicely in fridge
But there are times when I want something more…

"Airlock" vessels allow gasses to escape, but they do not allow them to enter. Fermentation produces carbon dioxide; in an airlock vessel, this carbon dioxide largely displaces the other gasses originally present inside the jar, including the oxygen. "Good bacteria" are perfectly happy without oxygen, but some of the enemies of delicious fermentation need oxygen to flourish. Thus the airlock tips the balance in favor of delicious fermentation.

This advantage can be particularly useful when making cucumber pickles, for instance, or other whole, brined vegetables; too much oxygen can lead to mushiness. Even regular, dependable sauerkraut can sometimes benefit from an airlock.

Airlocks also prevent the buildup of pressure. Depending what you're fermenting, this may be more or less of an issue. Fruits and high-sugar-content vegetables, for instance, can generate lots of gas when they ferment; while they're unlikely to break a mason jar, they could potentially pop a lid and make a big mess.

A few years ago, I posted a comparison of two of the available options for airlock fermenting: Pickl-It Versus Harsch: May The Best Vat Win. Pickl-It won.

Since then, more options have emerged. They are all similar to Harsch and Pickl-It in principle—in fact some are so similar that I would call them knock-offs.

Anyway, here are some of the airlock arrangements we can choose from today.

Old School

The Usurper

See Pickl-It Versus Harsch: May The Best Vat Win for my full comparison of these two. In short, the Pickl-It delivered better results, was a more manageable size, and was easier to clean.

The Clone

One of the newcomers seems indistinguishable from Pickl-It. Perhaps it is actually made by Pickl-It:

[UPDATE: According to an anonymous tip, Primal Pickler is a copy of the Pickl-It design, and is not made by Pickl-It.]

Old School, Eastern Style

This one uses the same general design as the Harsch, but it is made entirely out of glass instead of crockery. Intriguing. It has advantages over the Harsch: it is easier to clean; it may fit in the fridge; and it is clear, so you can see how your ferment is proceeding. On the downside, the Amazon reviews raise some questions about its durability:

Holey Cap

Picture a Mason jar whose lid that has a hole in it just the right size for a standard homebrew-style airlock (with or without stopper):

An advantage is that Mason jars are cheap and available in a variety of sizes; your lid will work on a wide range of jars. And once the fermentation has reached a stable state, the lid may be moved to another jar for the next project, and the first ferment can be sealed with a regular lid. The disadvantage of all of these products is that the lids are made out of plastic. I don't think this is the end of the world, since your ferment should not be coming into contact with the lid anyway. And two of them (Kraut Kaps and reCAP) explicitly state that the lids are BPA-free; this is a step in the right direction. (As a side note, did you know that until recently, Mason jar lids had a coating of BPA plastic on the inside?)


Another option is to make your own airlock vessel. Plain plastic lids for Mason jars are cheap and plentiful. You can cut or drill holes in them without too much effort. Standard airlock stoppers are tapered, so the measurements of your hole need not be precise. Making your own airlock lid will be the least expensive option by far. The drawback is that your lid is plastic.

You can also drill a hole in a metal or glass lid. If you already have the necessary tools and skills, this might be a good option. If not, you are probably better off going another route.


What is the best airlock system for you? You might not even need one. But if you'd like to try one, consider the advantages and disadvantages of each option, and make your choice! None of these products is right or wrong for everyone.

I hope you find this post helpful!


Unknown said...

I like how you lay different options out there, clearly and concisely listing pros and cons, and then cheerily encourage us to delve in, without worry of making the "wrong" choice. Your book, Real Food Fermentation, is like this also.

Perhaps you could be considered the ultimate fermentation enabler.

Alex Lewin said...

"Fermentation enabler". I will bear this title proudly--I love it! Thank you!

Anonymous said...

Primal Pickler is not made by the original Pickl-It, it is an unauthorized copy.

It is with disappointment I read that you are now recommending many of the cheap plastics based fermenting lids.

Many people are experiencing poor fermenting results as plastic lids do not produce the hermetic seal of a Pickl-It jar.

Alex Lewin said...

Dear Anonymous,

I'm sorry that you are disappointed by my post.

As I reread the post, it doesn't sound like I'm unequivocally recommending the cheap plastic lids. I do mention, twice, that being plastic is a disadvantage. I've had good results with these lids myself, and I haven't heard any of the negative feedback on them, but I'll keep my ears open. And if you know people who have had bad experiences with the plastic lids, please do send them here to post! I would be very interested in hearing from them.

As to Primal Pickler, thanks for the information. I have amended my post to indicate that Primal Pickler is a copy of the Pickl-It design, and is not made by Pickl-It. I'm not sure the notion of "unauthorized" applies unless the Pickl-It folks hold a patent or have one in the works. I didn't see anything to indicate that they did, but I definitely don't know for sure.