This is one the most frequently asked questions in just about every workshop I teach. The simple answer is “a long time”. In fact, fermentation has always been one of the ways to extend the shelf life of food.
The more nuanced answer is, “It depends”, on factors like your storage conditions, the temperature, the nature of the fermented food or beverage, etc.
This cheeky response is even more true when you realize that different people have different tolerances for funkiness! So, my usual advice as with exploring or eating anything (fermented or not!) is to
Trust your Senses!
Your body is equipped with many senses to navigate its world. Those senses will tell you ultimately whether something is good for you.
That said, here are some guidelines on the shelf life (in a refrigerator, unless otherwise noted) of the most common fermented foods once they’re done fermenting.
| Ferment | Shelf Life (in refrigerator) | Comments |
|---|---|---|
| Kimchi | 3 months | once it's too soft/sour to enjoy fresh, use it in a stew! |
| Sauerkraut | 3 months | |
| Cucumber Pickles | 2 months | Depends on how much salt you used; could be longer if kept whole |
| Pickled Veggies (beans, escabeche, giardineira) | 4-6 months | carrots, cauliflower and dense veggies hold up especially well |
| Kombucha | 1 month | Some flavors like watermelon and strawberry are more ephemeral; drink them within 2 weeks |
| Kefir (milk) | 1 month | becomes very sour after that; can be used to make other products after turning too sour to drink |
| Miso | unlimited | properly sealed, miso can easily last 10 years |
| Water Kefir (tibicos) | 1 month | Some flavors like watermelon and strawberry are more ephemeral; drink them within 2 weeks |
| Hot Sauce | 2 years | can be stored in pantry too (will reduce shelf life somewhat); surface yeast may re-form if in pantry |
| Sourdough Bread | 3-4 days (room temperature) 2 months in freezer | Never store bread in the refrigerator! If freezing, pre-slice bread for easy retrieval and keep in sealed plastic bag |
Author and founder of Fermenters Club. I’ve been fermenting food for 14 years.
In 2024, I published my first book, Fearless Fermenting.
When not stuffing things into jars, I enjoy permaculture gardening, cooking, yoga, writing, and studying cosmology and esoteric traditions.
Hi Austin,
I emailed you the photo and haven’t heard back but I did a little research online and I found this on Reddit: https://www.reddit.com/r/Koji/comments/nsyumf/white_specs_in_miso_if_you_look_closely_you_can/
My photo looked just like the one in this post. Does this sound reasonable to you?
That is a good guess that they are new protein formations (like you’d find in aged Parmesan cheese). It could also be salt deposits. It is not likely mold given that they formed in places not exposed to air.
Hi – I took the Miso class last spring at the San Diego Craft Collective. I made the half chickpea, half adzuki bean mixture. I waited the six months until November to have some and it is delicious. Now it has been in the fridge since then and I see there are some white spots all in the mixture. I wish I could upload a photo. Is that normal or is it mold? Does miso get moldy? Thanks in advance.
Hi MaryAnn,
Glad you’re enjoying your miso! Without seeing it, it’s hard to say, but mold on miso is unlikely. Do you remember putting a top layer of salt on the miso back when you set it up? That (now dried) layer of salt is usually what if anything is visible on the top. But you can email a photo to info at fermentersclub dot com and we can take a look!