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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.

Spoilage is a concern of many people, especially when they are just getting the hang of pickling and fermenting foods. It DOES occur. It is detectible when it happens (see our article on how to tell if food is spoiled). But what causes it?

Spoilage CAN occur from a range of sources. But the most common causes are actually NOT the things people think they would be.

Foods are most likely to spoil during two specific phases:

1. During the beginning phase, when the ferment is just getting started. This will be noticeable right away – the ferment never really develops the characteristic pickled or sour smell. Instead, it gets a funky smell (ok, so there just isn’t another word for it… if you smell it, you KNOW). It is NOTHING like the sharp smell of properly fermented foods. It is musty or odd, or something that just makes you wonder exactly what happened.

There are a number of potential causes for this, but only FOUR primary causes. (We used to have only two, but two new ones have cropped up.) Surprisingly, it is NOT because you forgot to wash your hands, or because you did not sterilize your containers, or even the strength of the salt in the brine. The first two have minimal affects – people used to brine foods under appallingly unsanitary conditions and it worked very well. The salt brine strength can help to compensate for questionable conditions to a certain extent, but not completely, and foods can be successfully fermented without adding salt (though we do not recommend it because the rate of failure is pretty high).

The primary causes for failure of the ferment to properly establish in the first place, include ONE that is a method issue, and three that are quality issues:

Failure to submerge the food. All of the food must be held under the brine. With kraut, a heavy weight must be placed on it to press the juice out of the cabbage and keep the cabbage pieces under the liquid. Failure to do this is the number one User Error issue.

So Rule #1 is: Keep the food under the brine!

Spoiled Food. If your food is starting to mold, do NOT use it for fermenting. You need good fresh food for fermenting. Even if you trim off the moldy parts, and wash it well, there is a very high chance that the foods you are handling have already been contaminated with a high degree of mold spores. It actually takes a lot to spoil a batch, and usually in combination with other factors. Sometimes a stronger salt brine CAN compensate for food that is on the edge, sometimes not, depending on the food, the water quality, the temperature, and the cussedness of the molds involved.

So Rule #2 is: Good fresh food that is not starting to spoil already.

Water. NOT well water – untreated water is NOT the cause of the majority of water caused spoilage. Chlorinated water is the culprit. Chlorine and other chemical contaminants in water are designed to KILL bacteria and fungus. That is why they are there. They aren’t picky about WHERE they kill those microbes (in the water, in your gut, in your foods, etc). In a ferment, that often means that they will kill the good bacteria, and let only the really resistant nasties thrive – and after so many years of government requirements for chlorine in municipal water, there are some really mean resistant beasties thriving in chlorinated water, and living in your kitchen. You get a yucky ferment instead of a good one if your water happens to be over-chemicalized, or inhabited with resistant microbes.

This is not a simple thing – some water has so little chlorine, and few enough resistant strains that the good beasties grow anyway and you get a good ferment in spite of it. Sometimes a stronger salt brine will help compensate, sometimes not. Sometimes a Brita or Pur type filter will be sufficient, sometimes not. On occasion, municipal water is so contaminated with chlorine and other chemicals that no amount of filtering (other than reverse osmosis) will clean it enough to get a good ferment. In general, winter ferments are more likely to succeed with municipal water than summer ferments – because pathogens are more rampant in warmer temperatures, water levels tend to drop in the summer, concentrating the contaminants, and some municipalities will compensate at times in the summer with extra chlorination.

Boiling the water only partially helps – chlorine tends to evaporate slowly out, but many places are adding chloramines, which do NOT evaporate.

So Rule #3 is to use clean water – good fresh well water, or cleanly filtered water.

Preservative contaminated food. That’s right, there are preservatives sprayed on your produce, and no labeling requirement to indicate that they are there! If you purchase non-organic pickling cukes with the spines removed, or cabbage from the grocery store, or other vegetables from the produce aisle in the grocery store, chances are, it has been treated with some kind of preservative. EVEN SOME ORGANICS ARE TREATED WITH CHLORINE, but organics still usually have a better chance of not spoiling in a ferment. Preservatives on your produce will cause foods to spoil, even when you do everything else right.

Detergents used to “clean” foods will also cause this problem. DO NOT USE VEGGIE WASH on your foods if you are fermenting! Plain clear UN-CHLORINATED water is the best choice, NO detergents.

So Rule #4 is to purchase FRESH food, LOCALLY if possible, ORGANIC if not possible.

2. At the end of the storage phase. A ferment will progress through many phases of bacterial and yeast life. As one form of food is consumed, the microbes that consume that food will multiply, thrive, and then die off. As they do, they are replaced by the next cycle that consumes either what the first batch did not consume, or the byproducts from the first batch. The food may progress through many phases of this kind. Eventually the food sources for healthy microbes wears out, and there is nothing left but fodder for the unhealthy ones, which will take over, resulting in a fairly marked and rapid spoilage of the food – mold, slime, squishy feeling, gray color, and unpleasant smells, all of which tell you this is no longer food.

All ferments eventually spoil!

The problem is when they spoil too soon. After only a few weeks, or a few months. Good ferments, properly stored, should last 4-6 months if stored in a root cellar, and FAR longer if stored in a fridge.

There are THREE main factors that affect this. Again, it has less to do with the finer points of handling, and more with the biggies.

Temperature: This is the most influential factor. Cool temperatures, down to about 40 degrees, keep ferments fresh longer, as a general rule. There are some that don’t thrive at low temperatures, but they usually STORE best at lower temps. Your typical kraut, pickle, or condiment ferment stores best between 40 and 50 degrees.

Freezing will kill some of the bacteria, and leave it ripe for infestation by nasties when it warms back up. Higher temperatures mean that the fermentation progression just happens faster – sometimes WAY faster.

Keeping the Food Under the Brine: Again, this is a prime factor. Keep the food dunked, and it will be preserved much better. Small bits usually are not the issue. Big bits are. If they stick out of the brine very much, they’ll mold before they cure, or degrade faster after they cure.

Brine Strength: More salt generally means it stores longer. Successful ferments can be achieved using a wide range of salt concentrations, but as a rule, the heavier salt concentrations lead to a longer storage life. Salt can also help to offset other factors that may be less easy to control, but usually only to a certain extent – it can’t compensate for everything, and it can’t do it indefinitely. Eventually even the saltiest of foods will be overtaken by opportunistic microbes that do not have your best interests at heart.

Fermenting is NOT as complicated as it may seem at first. There really are only a few things that you absolutely HAVE to get right. The rest is artistry – improving on a good thing, simplifying or increasing the predictability in your results. The factors listed above are the key elements in controlling spoilage. Everything else is just a nudge factor.

SPECIAL NOTE: Airlock lids and anaerobic environments are NOT discussed in this article, because they are NOT critical factors regarding spoilage. SOME individuals MAY be sensitive to specific bacteria or yeast types that proliferate less readily in an airlock environment, but as a rule, an airlock is NOT required to prevent spoilage.

From a CONVENIENCE standpoint, an airlock DOES make the process SIMPLER, because you do not have to vent the jar, and you MAY be able to be less picky about keeping things completely submerged (we are still testing this, and this statement is only based on preliminary observation, not side-by-side testing). Generally an airlock is not required to eliminate or SIGNIFICANTLY reduce spoilage in fermented foods.

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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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.
Uses of Fermenta Lock

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.

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. A wonderful innovation. I have not lost a single batch of sauerkraut since I started using the original Fermenta Locks.”


“Please continue your good work on producing such a great product. I’ve tried lots of other kinds of airlocks- the 3 piece water lock, pickle pipes, fermilid, boss pickler, and I think yours is the best design and quality. I’d like to order another 100 of them right now, but I’ll have to wait a bit. I’ve had lifelong health challenges. I’m 38 and about 20 years ago my health was so bad I didn’t feel like living most of the time. Now my health is the best it’s ever been and it wouldn’t be possible without fermented vegetables, they have made a huge improvement in my health.”


(Last names omitted to protect customer privacy.)