I get this question in various forms all the time. How long can fermented foods be left to ferment?
Did I ferment my sauerkraut too long? “Help! I went 10 days by mistake, but the recipe said 7 days! Is it bad?”
I’m not surprised I get this question all the time, because there is so much conflicting information out there. Some recipes will say to ferment sauerkraut for 3 days while some say 3 months. Same for fermented veggies.
Is there really a set fermentation time for fermenting vegetables? The short answer is no. It varies and depends on a few factors.
The number one factor that affects fermentation time
There are many variables that can affect the time it takes for your suaerkraut, pickles, fruit and even kombucha and water kefir to be ready. Fermentation time varies depending on the temperature of the room you’re fermenting in.
Temperature
Temperature affects the speed at which fermentation occurs. A cooler room will slow fermentation while a warmer room will speed it up. Ideally most ferments do best in an environment that’s at a comfortable room temperature, about 60 – 75 degrees fahrenheit.
Hot weather
During the summer the temperature of the kitchen rises. The heat speeds up the activity of the bacteria and can make a typical 5 day ferment be done in 3 days.
Cold weather
During the winter, if your kitchen is cold, a typical 5 day ferment could take as long as 7 or 10 days. Even two weeks. It’s safe to ferment for a long period of time.
Salt
The amount of salt you used in your sauerkraut or fermented vegetables will affect fermentation time. Too little salt will speed up fermentation, but may cause it to become slimy and develop mold. Too much salt can slow down fermentation significantly.
Learn My 3 Simple Steps to Get Perfectly Salted Sauerkraut Every Time here.
Personal Preference
Time can depend on taste preference. The flavor of pickled vegetables and sauerkraut will develop and get more complex over time. Textures can change too.
If you like your sauerkraut more crunchy, then ferment it for less time, if you like it more soft, let it go longer.
Pickled vegetables tend to be more crunchy the less they ferment too. But that also depends on the texture of the vegetables. Carrots hold their crunch very well, while radishes will get softer the longer you let them ferment.
Some people believe that the longer you let it ferment the more bacteria will be present. Some people let their sauerkraut ferment for at least 20 days in that case. Some people think the opposite is true.
What should you do?
Personally I let all my vegetables and sauerkraut ferment until the pickle brine is cloudy or the sauerkraut is bubbly and then I do a taste test. If it tastes sour and I like the consistency, I’ll put it in the refrigerator to eat. If I don’t think it’s sour enough, I will leave it out longer to ferment for a few more days and taste it again.
I think you should get comfortable with tasting your ferments too. You’re only going to eat it, if it tastes good to you.
Don’t worry if your ferment is taking longer than instructed, because time can vary significantly depending on these factors.
So, how long can fermented foods be left to ferment? As long as you want.
You can let your vegetables and sauerkraut ferment for several weeks, months or days. It depends on temperature, salt and your personal preference. Experiment with your own ferments and you’ll find a process you like best.
How long do you like to let your sauerkraut, pickles or other foods ferment and why? Let me know in the comments below.
Happy Fermenting!
-Danielle
I usually let mine ferment in the air-lock crock for a couple of months…. but I had a 6 quart batch ready to put in jars the first of August, but had a bad fall and broke both arms requiring surgery and a very long healing time. I was finally ready the middle of January to deal with it and it is a seriously delicious batch. I’m on my last jar.
I use mostly air lock Mason jars and typically my veggie ferments aren’t sour enough for me until at least 2 months. I tried a kimchi box for the first time and things moved twice as fast though!
My wife is Chinese and the Chinese have a little different method than us. Recently my wife’s parents came for a visit and they started fermenting all kinds of different things none of them ever are put into the fridge. They leave them tightly sealed and don’t open them until they are ready to eat. The most amazing thing they pickled were limes. They were left outside sealed in a jar in the sunshine, they went brown and looked bad to me. Six months later they brought them in and made a delicious spicey paste that was unbelievable. Anyway the point of my story is we have a lot we can learn about fermentation from other cultures.
I used to do what some websites that don’t mention using air locks say to do – remove the lid every day or two and check for mold; if there’s mold remove it with a spoon. About half the time or more, I had mold. Sometimes it grew so fast that it ruined the flavor of the product before I could remove it.
Now I always use air lock lids and I NEVER remove the lid to check on anything until I’m ready to put the jar into the refrigerator. Since I have started doing this, I have never had any mold or bacterial rot. If the batch is good but not to my liking, I will change something on the next batch but I’m not taking that air lock off for anything until it’s time to eat the stuff.
The last batch of kraut I made was from two heads of red cabbage (two quarts). I’m not allowed to ferment in the house so I had it in the garage where the daytime temp exceeded 90 deg F. I brought the first quart in after a week and it was OK. The other quart stayed out there another week and then was in the refrigerator at least 3 or 4 more weeks while I ate the first quart. Of course, when the jars go into the refrigerator I put regular lids on them.
When I started eating the second jar, it was delicious – less salty and more tender to the tooth with, generally, a better or more interesting flavor.
My advice is to relax. This is not like making pastries where the recipe has to be followed to the letter or you’ll wind up with a baked hockey puck. If you stay inside the ballpark, generally you will be OK. If you have a failure (mold, rot or stench), it’s OK. Learn from it and move on. :)
My other bit of advice is to invest in a couple of air lock lids. I know they seem expensive for what they are but they are worth it in successful fermenting and peace of mind.
Good advice! Thank you for sharing :)
I’m with you, I don’t remove the lid until it’s done! I took a microbiology class and learned a lot. In fact, I do lots of veggies right in mason jars with the white plastic lids. I overfill them so the brine spills over, put the lid on which pushes more liquid out so there is *very* little to no air in there. I put a deep dish or tray under them to catch drips, and for the first few days I might burp them when they’re at their bubbliest, but after that nothing more is necessary. They will remain anaerobic until I want to eat them, then I refrigerate them once opened. I’ve only been fermenting about a year (kraut, cukes, mixed veggies, beets) but I’ve never had mold yet. I only had a pink yeast film once, when I taste tested and let it go another week or two, so I definitely agree with you! :-)
Isn’t there carbon dioxide that is produced which needs t vent?
Yes, it leaks out on its own when I use the white plastic lids meant for the mason jars, or even an old pickle jar with the metal lids that have the white waxy coating inside. I tighten them a normal modest amount; I don’t force them tight, but they’re tight enough that they wouldn’t spill if I tip them over. Without me doing a thing they fizz out gas & liquid. The first time I tried it I checked on them several times a day, expecting to have to ‘burp’ them, and fearing an explosion, but they were fizzing out gas & liquid on their own! I’ve done over a dozen or two jars this way over the past 6-12 months, and now I don’t even pay attention to them unless I’m curious and feel like swirling them around a bit. I put them in the corner on an old baking sheet, write on the calendar a month ahead when they’ll be done and forget about them until that date comes up.
cultured guru website say 21 days to get the broadest and highest concentration of probiotics for sauerkraut. they’re biologist lab nerds and have done all the testing to back it up
Yes, I don’t have time to look up the studies but I’ve seen them. In addition, you actually should NOT eat fermented veggies within the first few days, and I like to figure the first week just to be sure. The bacteria that are most prevalent at that time are not probiotic. They may be neutral and not hurt you if you’re fairly healthy (not sure, look that up for yourselves), but the good stuff doesn’t start taking over until about a week. Those first few days or week of high-level fizzing are the non-probiotic bacteria multiplying and producing CO2 which pushes the oxygen out and makes the environment perfect for the good bacteria, which THEN take over and multiply fairly silently. Good rule of thumb: don’t eat it until the main fizzing has stopped. I let everything go to about a month to feel like it’s worth it for health purposes.
(does this make me a nerd, too? :-p )
I have been fermenting for a little while. Sometimes it gets quite fizzy and vegies a are soft, is this ok?
Yes. The longer they ferment the softer they get.
Thanks Danielle, have you ever had any get a fizzy look and feel?
Yes. Most get fizzy.
I started a batch of sauerkraut about 3 weeks ago, portions of the cabbage in the jar is opaque and other portions look like fresh cabbage. Should I leave it to ferment till it is all the same color? I did taste some of the opaque color and it is actually quite good
If you mean opaque, cloudy liquid, that’s the bacteria, which is the probiotics. It’s usually settled at the bottom. Sometimes I swirl the jar a bit, hoping to spread it around. If you mean the cabbage is becoming transparent, that would be the cabbage breaking down and becoming softer as the bacteria eats it. Transparent or opaque are both ok, whether on the cabbage or the liquid. :-)
I sterilized a big Mason jar and boiled bigger rocks to put on the cabbage along with a piece of Saran Wrap. Only second time fermenting purple cabbage but the boiled rocks work well!
I used some glass “gems” I picked up at Walmart to put on top of the shredded cabbage to keep it submerged in the brine. I’ve been a little perplexed over how to sanitize them before adding them to the jar. Then I read your comment and went, “Doh, boiling, of course!” Thanks for sharing that.
I would be careful, some of those types of glass may contain lead. You can use pie weights as a replacement as they are meant to be used with foods.
I was cleaning out my pantry and found a jar of sauerkraut that I had made well over a year ago but had forgotten about. Out of sight, out of mind. Anyway, I opened it up and did a sniff test and it smelled great. So, I decided to do a small taste test and other than being slightly softer than I normally like, it was incredible! I ended up eating an entire bowl full! I’ve been making my own vinegars and kombucha as well as fermented asparagus, watermelon rind, garlic and lemons (not together though. Yuck.) for some time now but other than my fruit vinegars, I hardly let anything ferment for more than a few months at most. I was sure I would have to compost the sauerkraut. But to my delight, it’s still good! Best sauerkraut I’ve ever made! I guess we’ve been so conditioned to toss food out when it gets some age to it, fearing it will cause some sort of food born illness.
I forgot about pickles (cucumbers) for 3+ months. NO WAY!! LOL, there was no mold or foul odor but they were so waterlogged and mushy I couldn’t even pick them up with tongs, lol, they split open and fell apart from being bloated & mushy. Other than that I’ve been a one month person. Glad to hear the sauerkraut was good for so long. I suppose it depends on the water content or structure of the vegetable. After one month, I found celery to be too mushy, so I don’t include it in my mixed veggies anymore. My favorite combo so far is string beans, carrots, cauliflower, onion ,& garlic, with some peppercorns and dill seeds, one month. My son doesn’t like those veggies so I’m about to try a mixture of root vegetables with onion & garlic for him because he did like the radishes (it bugs me that they turn everything pink though; after my pink yeast episode it reminds me of that, lol). The onion & garlic is great on sandwiches or cheese & crackers. Thanks for your experience and ideas :-)