Storing your pickles safely while they ferment

In this post I run down different ways to store pickles mold-free while they ferment. Storage is a crucial aspect of making pickles and there’s more than one way to do it. Every technique achieves the same essential goal, though: keeping the pickles from being exposed to the air for too long. Otherwise, mold may gain a foothold and begin to grow. In most cases this means you want to keep the pickling food submerged in brine, away from the air.

On the other hand, it’s important to keep the surface of that brine open to the air. If you seal the pickle tightly with a lid, carbon dioxide—a natural byproduct of fermentation—will build up and create pressure that could cause leaks or even spray pickle juice everywhere when you open the lid. Salt-brine pickles ferment at room temperature, not in the fridge, and it’s best to leave them in a dark place like a cabinet. Because the jars stand open to the air, it’s a good idea to cover them with a towel to keep out dust and random flies. It is also wise to put your jar on top of a kitchen towel or in an open tupperware that will catch any drips.

Pickling can take as little as a week and as long as a month (or even longer) depending on the size and density of the food you’re pickling. The bigger and harder it is, the slower it pickles. The temperature of your storage space influences the timing too. The hotter it is, the faster the microorganisms will do their work. The good news is that it’s hard to over-pickle something. If you’re not sure your pickle is ready, give it a taste. When it tastes the way you like, remove your seal, put a lid on the pickle, and put it in the fridge. This will stop the fermentation, although the flavors of your spices will continue to soak into the pickle.

So, here are some techniques for keeping your food mold-free while it ferments:

herring jar seal

1) My favorite technique is to use a weight, preferably a sealed jar full of water that is small enough to fit into the mouth of your pickling jar. In this picture, a jar is keeping fermenting herring below a brine of salt water and whey.

curing olices jar seal

Here the jar is at work keeping curing olives under a salt brine. You can also use a rock or any other heavy object that you feel won’t affect the flavor of your vegetables. When using this technique, it’s a good idea to leave at least an inch of clearance between your food and the top of the pickling jar so that the weight can sit well inside.

kraut sealed with a plate

When the food is finely shredded, like the sauerkraut in the picture above, it is helpful to use a plate, glass lid, or wooden round that fits closely to the sides of your fermenting crock or vessel. Then you weigh down the plate with something heavy, like a jar (or jars) full of water. If the seal isn’t close enough to the edge of the vessel, the pickle will float up around the edges.

radishes cut for vegetable seal

2) Another option is to use a larger piece of vegetable as your seal. In the picture above, I’ve cut two long, thick slices of radish.

vegetable seal

Then I packed them cross-wise into the jars so that they folded under the edges of the jar top. This forms a barrier that holds the other vegetables down, even when the jar is filled with brine to the level of the seal or above. Large, hard vegetables like carrots, radishes, and beets work best.

If your brine covers the seal continuously throughout the pickling process, you’ll be able to eat it too. If some part of the seal pokes above the water, I recommend throwing it away when you move the pickles to the fridge.

veggies packed tight to seal

3) Sometimes you pack your pickling jar so tight that it doesn’t seem like anything will budge, like with these squash pickles. In that case, just fill the brine above your food and let fermentation happen. If you go this route, though, be careful to check your jar often (every day is good). Veggies tend to soak up the brine, swell, and float loose while the brine level sinks. What you thought were well jammed veggies may start poking out into the air in a few days. Keep track of them and add more brine or stick on a weight if this happens.

pickled lemon shaken

4) You can also keep mold at bay by shaking your jar once or twice a day. A vigorous shake (with the lid firmly sealed, of course) will move your pickle around, sending the food at the surface deeper into the jar, where any mold will be doomed. You can also flip your jar once a day, turning the top into the bottom every 24 hours. When the jar is upright, leave the lid only loosely tightened to allow carbon dioxide to escape.

This works best with a pickle that comes in smaller pieces and is meant to be soft and mushy, like these pickled lemon slices, or Indian lemon pickle.

5) If you want to get even more hands on you can use your fingers to push the vegetables under the brine every day. This is most effective when making a mushier pickle like kimchi. I’ve heard this recommended but never tried it myself. I prefer the confidence of sealing my pickles with a jar and knowing they’ll be safe from mold until I’m ready to eat them.

  1. Yuan’s avatar

    I actually use a Chinese pickling jar that uses a water seal. Really cool. I’ll send you a picture at some point. I have no idea where you can find one in the states though.


  2. Jim’s avatar

    I am having issues with having to “burp” the jars that I put in the fridge a day ago. I fermented the pickles for 4 days, which gave then the crunch and flavor I was looking for, but it seems like having the jars in the fridge has not stopped or slowed the fermentation very much. I use the Fido glas jars with wire bail-type closures and rubber gaskets and I have to undo the latch and very slowly let the pressure out by keeping some hand pressure on the lid. I am hoping this will subside soon. I have another batch that i am going to leave on the counter to ferment a couple more days so that the fermentation process is more complete. Hopefully that will also help solve the problem.

  3. Jessica’s avatar

    A friend of mine gave us some homemade pickles. We just opened the jar and brine sprayed everywhere! Are they safe to eat?

  4. Eric’s avatar

    @Jessica, that’s hard to say without knowing more. Did they go through a heat canning process? If they did, then I’d be worried about eating them because the fizzing shows that not everything was sterilized. If they are live fermented in brine, then they may be OK so long as you don’t see mold on them. I’d ask your friend for advice.

  5. syed sharekh’s avatar

    I made some fermented raw mango pickle , it was very tasty and good textured, but after 3 months it gets very soft texture.
    so anyone can tell me the solution

  6. Eric’s avatar

    Hi Syed, It is normal for the mango to get softer over time. Did you start with green mango? Green mango stays hard longer.

  7. syed sharekh’s avatar

    yes eric ! i used sour varity of green mangoes for pickling .
    indeed i want to stop the fermentation after certain stage.

  8. Eric’s avatar

    Hi Syed, you could stop the fermentation by canning them and sterilizing the jars of pickle in a hot water bath, although that will kill the beneficial bacteria. Otherwise I’m afraid I don’t know what to say except to eat them more quickly!

  9. syed’s avatar

    thanks Eric for aiding me

  10. Diana’s avatar

    Hi Eric, I have fermented some cucumbers, and there is mold on the top of the brine. Somewhere I read that this is not dangerous, but I’m not so sure. What would you do?

  11. Eric’s avatar

    Diana, I would scrape the mold off and keep the cucumbers. They should be fine if they’re under the brine.

  12. saranya’s avatar

    I have some Indian green mango pickle, that was initially well layered with gingelly oil. but with use, the oil just gets mixed with the pickle. i was out for a month and when i returned, i found a blanket of green mould growing on the surface. Is it safe to scrape it away and keep the pickle or would be toxic?

  13. Eric’s avatar

    Hi saranya, yes that is usually safe to do. I would try to gently spoon the mold off of the surface. Then check the mango right underneath to see if it is extra mushy or discolored. If it is, then throw out that mushy layer, too. Also look at the sides of the jar because sometimes there are little air bubbles in between the mango pieces, and if there is green mold in those air bubble spots then I would throw out all of the pickle. The goal is to get to the mango that hasn’t been touched by the mold growth.

  14. Nate Capton’s avatar

    I have made brine pickles in a crock in my basement can I mover them to the fridge and if so what can I put them in and what do I put them in (liquid)?

  15. Eric’s avatar

    Yes Nate, I would put them in a jar and pour in the brine from the crock to cover them. If there isn’t enough brine you can mix up some more and top it off.


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