Can You Ferment Different Foods in the Same Room

The other day a friend of mine popped over with some old wine that had turned. He told me he couldn’t keep it in his kitchen because he had some wine fermenting in that space and he was afraid this vinegar-wine would affect his good wine. He thought maybe I’d like to make some vinegar out of it. Hmmm… Wow. I gave this some consideration and decided to do some sleuthing.

You see, I ferment all kinds of things in my kitchen! At any given time, I have herbal ale, kombucha, lacto-fermented vegetables, cheeses, and other things going on. Never once had I given any thought to all these different ferments, with all their different types of bacteria and yeasts potentially affecting the others.

Normally, I wouldn’t have given this a thought and accepted his wine-turning-into-vinegar gladly and gratefully. But I started to wonder: How safe is it to have several kinds of ferments going on? What are the potential problems, anyway?

Can You Ferment Different Foods in the Same Room?

It’s all about cross-contamination. You see, yeast and bacteria are microscopic beings. They are floating about in the air all around us all the time. For some fermenters, taking the chance of the aceter-bacter from vinegar accidentally ending up with the lactobacillus in your veggie ferment is a horrifying thought.

However, my own personal opinion about whether or not it’s safe to ferment different things in the same room is opposite of the nay-sayers. I think it’s fine…with a few caveats.

Here are the things you need to understand and know, then you can make your own decision about whether or not to allow your different types of ferments to be in the same room.

How Does Cross-Contamination Happen?

Different cultures contain and need different kinds of bacteria and yeast for a successful ferment. For example, the bacteria and yeast in kombucha are very different from those found in home brews or lacto-ferments or cheeses. Some of these bacteria may be “good” in one type of ferment but are “killers” to other types of ferments. This is why my friend refused to keep that wine-turned-vinegar in his kitchen with his culturing wine. When you begin your fermentation journey, it’s a good thing to know that not all cultures are the same.

Cross-contamination is when bacteria or yeast get into a ferment when they don’t belong there. This can cause strange tastes and odors and may even affect the health of the culture. It’s happened to me.

I opened up a beautiful jar of fermenting green tomatoes one time, and a thin film of Kahm yeast stared back at me. I sure didn’t welcome it there.

So how did that Kahm yeast get into my purified jar of green tomatoes?

It could have happened in several ways:

  1. Perhaps I didn’t completely clean out the jar those tomatoes were in.
  2. Or, perhaps my hands weren’t that clean.
  3. Or, maybe, just maybe that wooden spoon I used harbored some spores I didn’t know about.
  4. Or maybe those little beasties just floated through the air and entered the ferment.

These are some of the ways cross-contamination can happen, but these incidences can be alleviated by following a few best fermentation practices.

How to Prevent Cross-Contamination

  1. Make sure all your tools and utensils are very clean. Some people believe you need to sterilize everything, but I’m not in that camp. Hot water and soap are all you need. I like to spray my counter with a vinegar/water/essential oil cleaning spray to make sure any bad bacteria are gone.
  2. Keep your ferments away from each other. I’ve heard anywhere from two to four feet, depending on different friends’ experiences. I have a small kitchen, so my cultures tend to be roughly three feet apart.
  3. Keep your culturing foods covered appropriately. Some need airlocks. Some need lids. Some need cheesecloth. Just be sure they are secured well on top.
  4. Make sure your garbage can and kitchen composter are well away from the area you use to prepare your cultures and the areas they are being stored.

Final Thoughts about Culturing Different Types of Ferments in the Same Room

Personally, I’ve been fermenting a variety of foods in my kitchen in perfect harmony for years. Cheeses, kombucha, lacto-ferments, and more have been happily cohabiting the space, and except for the Kahm yeast issue that one time, I’ve never had a problem.

I think it really boils down to understanding that yes, cross-contamination can happen, and then, of course, doing everything you can to prevent it. After all, a strange bacteria or yeast you know nothing about can potentially affect a culturing ferment. You just have to take precautions.


For more instructional tips to help you on your fermentation journey, check out the following posts:


Heidi Villegas is a writer at Healing Harvest Homestead and loves sharing her experiments with the world. She passionately studies herbalism and traditional skills, using her pioneer ancestry as a foundation. Heidi loves her animals, gardens, and making things herself. She became interested in fermentation after experimenting with making her own fermented foods and realizing the health power they have! Heidi lives off-grid with her husband, horses, goats, chickens, turkeys, ducks, cats, and dogs on a small homestead in the Mojave Desert.

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