Cap Uses

Fermenta Lock is a compact airlock cap for mason jars, to help in making old fashioned brined pickles, and other lacto-fermented foods. Use Fermenta Lock for:


Pickles (all kinds)
Sauer Kraut
Milk Kefir
Bean Paste/Hummus
Sourdough Starter (if started with culture or yeast)
Anything which needs gas release without a lot of air circulation.

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Fermenta Lock Airlock Cap

$9.50 each
$9.30 per unit for buying at least 5
$9.15 per unit for buying at least 10


Wide Mouth Compact Airlock Jar Lid. Fits standard Wide Mouth Mason Jars and other jars which accept the same size lid. Also available in other standard jar lid sizes.

Each order includes:
1 Wide Mouth Fermenta Lock Airlock Lid
and 1 Wide Mouth Storage Lid

NOTE: Standard Mouth Fermenta Lock Caps are available by custom order. Just Order the Wide Mouth lid, and email us to let us know that you want Standard instead. They are a custom order item, and may take longer to ship than other items since we do not stock supplies for them due to low demand.

Fermenta Lock is an entirely new airlock lid. No cumbersome water lock to mess with, no awkward thingy sticking up off the top of the jar - you won't have to worry about putting it in the fridge, or knocking the airlock off!

Article on How to Use Fermenta Lock

A smooth and elegant one-way valve lets air out, but not in. Pops out easily for cleaning, no clumsy latches or inaccessible parts. Use the airlock lid during fermenting when gas release is important. Use the Storage lid to store the food in the refrigerator long term when gas release is no longer an issue.

Easy to use - just screw on. Nothing else to do, it just works!


How the One-Way Valve works

The one-way valve is a traditional concept (this kind of valve has been used in many applications for a very long time). Pressure from the outside is deflected down around the curve of the cap, instead of through. Pressure from the inside pushes through, because it is not deflected.

This is the same way an egg stays strong from the outside, but still allows a fragile new chick to break it from the inside.


Manufacturing Note: Fermenta Lock is manufactured by us, in a hand-casting process. We have done this to be able to provide the product made of Silicone instead of from Latex, and to simplify to a single piece valve - something we cannot do without custom manufacturing (and we are NOT comfortable contracting that to China!). Food grade materials are difficult to work with, and our product LOOKS a little rough, due to imperfections in the casting processes. The product WORKS great - the sealing surfaces are smooth and tight. It just looks and feels somewhat nubbly, and some of the edges do not line up perfectly. These are some of the compromises we made in order to bring you a product we feel good about recommending for your kitchen.

This unretouched picture of the valve shows the roughness we are talking about.

The choice to manufacture this ourselves was not made lightly. The only pre-made parts available are made of latex, which we are not comfortable with, due to an alarmingly high prevalence of latex allergies.

Silicone, plastic, and rubber materials manufacturing is a very complex thing. Finding Food Grade materials at an affordable cost is difficult to begin with, and having an item custom made requires a very large up-front financial investment, which we did not feel was practical at this time. FDA requirements for food grade silicones and rubber are not a simple thing. It does not only have to do with the ingredients which form the basis of the material, it also has to do with how they are manufactured - the hardeners, solvents, and other chemicals used in the manufacturing processes. There is great room for error, accidental or deliberate.

We had two choices: make a product ourselves, with KNOWN materials (by obtaining pre-mixed materials already certified to be food grade), or to contract the process out to a company in China. Given the recent issues with contamination of products imported from China, plus the disappearance of manufacturing from our own shores, coupled with the complexity of verifying FDA compliance for food grade silicone manufacturing, we decided that it was better to purchase certified food grade materials from US based companies and do the casting ourselves. Visible cosmetic imperfections seem preferable to a considerable risk of invisible potentially toxic problems.

In making this choice, we have committed not only to keeping our product quality the priority, but also we have committed to developing our company using cottage industry in as many instances as we can find the means to do so. Our choice to manufacture our own part has fundamentally changed the way we do business - putting into practice, in new ways, concepts we have long believed in and desired to support. Our business plan and model has been permanently altered, in amazing ways, because of this one choice.

Made in America! Lids manufactured in the US from BPA free plastic. Lid alterations performed in the US. Valves manufactured by hand in the US.

CopyCat Notice



The ORIGINAL one-way valve fermenting airlock! Imitation IS the sincerest form of flattery, and we have noticed that our product has been copied by other sellers of fermenting products. Remember, if you see someone else selling a one-way valve airlock for fermenting, THEY copied US, not the other way around! Fermenta Lock is still the only original invention, handmade in the US. If it isn't orange, it isn't the original!

We invented Fermenta Lock, Fermenta Free, and the valve used for Fermenta Fido and other Fermenta Airlock products. We invented Fermenta Dunk Extender. Patents are prohibitively expensive, and designed by the government not to protect the rights of individuals, but to provide another source of revenue and control for the government and lawyers. We are good at what we do. We have endless ideas and endless creativity, and competition does not scare us. Impatient thieves do not scare us - they are too busy taking shortcuts to make a success of it anyway, and they won't want to take the effort to actually MAKE a product and fill orders.


So if you want to copy our idea, go right ahead. If you want to market and sell a competing product, you are welcome to do so, as long as you do not patent our idea - we had it first, and our posts on FaceBook announcing the invention and launch of it will prove that. This idea is officially in the public domain, placed there by us. We will NOT release supply sources, or part names unless you want to buy them - we'll be happy to sell you an instruction kit. If you buy our product, or look at the images and figure it out for yourself, good on you. Compete with us if you like, just don't screw us, and we'll get along just fine. Big companies who might want to screw us may have more money, and more lawyers than we do, but we have more to gain by suing the pants off a big company, and believe me, we will be well motivated to do so if anyone patents our idea and claims it as their own - this is a free idea. Everybody now owns it.

Published June 23, 2012



Wholesale, Export, and Manufacture of this product by other companies is an option. International distributorships are available for those wishing to export. Please email us to inquire about access to our wholesale website, or in regards to manufacturing any of our products.


Business Building Services Are Available - If you are wanting to build a business like this, where you make things in the home and sell them direct to the customer, or if you want to build a business that you can sell to other people as a complete business package, Firelight Heritage Farm is now offering Cottage Industry Services to aid small business owners in building a successful product or service business from the home. Don't know what you want to do? We can help you figure that out too (something original, and just yours, not a canned business). You get the wisdom and uniquely successful perspective and experience of people who have been business, marketing, and website professionals for more than a dozen years. For more information, visit Why copy someone else's business when you can do something uniquely you and enjoy it so much more?



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(International Shipping quoted by email for each order.)

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This website is only equipped to handle orders from US customers (International shipping must be calculated for each order). International Orders are now accepted BY EMAIL from UK, AU, CA, and shipped USPS (other countries will be considered if requested). Please email a list of the items you wish to order, using our Contact page, and we will give you a shipping quote, and then invoice you from PayPal for the total.

Customer Comments

"Living down in Guatemala, we have quite a lot of dampness in our houses and mold is an ongoing battle. After a long dose of antibiotics due to a parasite, I absolutely required probiotics to get my gut back in order and I know homemade sauerkraut has more probiotic content than anything else I could find here. I wasn't able to make my beloved sauerkraut or even Kombucha in my kitchen because mold would start growing immediately on the top. Your Fermenta Locks have literally been a lifesaver for me! No more mold, and PERFECT Kraut EVERY time!!! Thank you for creating such a wonderful product!!!"

A. Kratzert


"Oh how I wish I had found you first!! Too many experts and too many bucks later I discovered your "Lock" and the sheer elegance and simplicity of your system.Thank you for your help and affordability, it makes healthy food attainable."



"I came back to order more FermentaCaps, this time the Fermenta Free version. A wonderful innovation on an already great idea. I have not lost a single batch of sauerkraut since I started using the original Fermenta Locks."



(Last names omitted to protect customer privacy.)


Fermenting is a science, and a bit of an art. It requires care in a few specific things, but doing it right is not particularly complicated. We provide instructions that are accurate to the best of our knowledge, and which are based on the methods we successfully practice ourselves. There are no guarantees of success or safety with fermented foods. While properly fermented foods are not only safe, but healthy to eat, it is up to you to follow instructions to ensure safety, and to trust your eyes and nose, and don't eat things that do not look or smell like food. We offer no guarantees of success with our product. We do warrant that it is as described, and will do what we say it will, but how you use it is your choice.


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