Did you know that if your ferments are too close together, you’ll experience cross-contamination?
That’s right. You can use clean containers, organic vegetables, and do everything else right…
…but if different types of ferments are too close together, weird things will happen!
Like “fluffy” cheese, yeasty or alcoholic-smelling vegetable ferments, and funky tastes.
So, how far apart should you keep your ferments? Which ferments are important to space apart and which don’t matter? What if your kitchen is too small to keep them far enough apart?
I’m covering all the “rules” on how far apart to space your ferments on today’s #AskWardee! Plus, I’m telling you when it’s ok to let things slide. 🙂
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The Question: How Far Apart To Space Your Ferments To Avoid Cross-Contamination?
Laurie D. asked:
I am newer to fermenting but am absolutely loving it! I’ve learned so much from you!
I’ve heard you say a few times that you need to keep your ferments separated by about 4 feet (I think that’s right?). I would love to know more about this. I don’t have a very big kitchen, so keeping my water kefir away from my kombucha and sauerkraut is getting challenging. Would a shelving system be okay to keep them separated, or is that just not enough space?
Thank you so much! May God richly bless you!
My Answer: The 5 Foot Rule
Laurie, it’s correct that the “rule” is your ferments should be 4 to 5 feet apart. This prevents cross-contamination of cultures, where yeasts and bacteria are getting into nearby containers.
We can’t see it, but here’s what’s happening:
There’s a cloud of microscopic activity surrounding our ferments. When the “cloud” around one container gets close to another’s cloud, the organisms share vessels. They hop back and forth. It’s kind of funny to imagine, isn’t it?
And when they’re sharing containers, you can end up with grainy cheese or cheese that puffs up into billowing clouds instead of forming smooth curds. Or you can get vegetable ferments that end up yeasty and cheesy smelling. And so on…
So, it’s important to keep the different “types” of ferments spaced at least 4 to 5 feet away from each other.
By types, I mean:
- fruit/vegetable ferments
- dairy or water kefir
- cheese
- sourdough starter or souring doughs
- Kombucha
- alcohol
- vinegar
If you have 2 ferments of the same “type” — say pickles and sauerkraut — they can stay close together. You can keep different souring doughs near each other. And, it’s ok keep different cheeses near each other.
In my opinion, though you may get some culture-sharing within types, the results are not usually as disappointing as when differing types of cultures cross-contaminate.
By the way, if you haven’t already grabbed our FREE Fermenting Formulas Cheat Sheet, go here to do so. You’ll get tried-and-true formulas for all kinds of ferments!
What If You Don’t Have Enough Room?
Laurie, you mentioned this is a challenge for you because your kitchen is small. A shelving system doesn’t solve this unless it’s tall enough that when you put one ferment on the top shelf and one on the bottom, there is 4 to 5 feet between them.
If you or anyone else is in a smaller space, here’s what I suggest:
- Space ferments as far apart as you can.
- Never keep your sourdough starter near other ferments, especially cheese or other culturing dairy.
- Move some ferments into another room… a pretty crock or vessel full of colorful vegetables can become a temporary decoration!
Our kitchen has 3 “corners” and I have ferments in each one: Kombucha in one, kefir in another, and sourdough in another. I have an additional area — the island counter in the middle of the room — where I keep vegetable ferments. It’s at least 5 feet away from each corner.
This is what’s going currently; we change it up from season to season depending on what’s culturing.
In the past, when we had a smaller kitchen, I kept some ferments in the dining room or living room that were adjacent to the kitchen. We had to make it work!
Additional Fermenting Articles
- Troubleshooting Your Ferments (KYF172)
- 5 Tips: How To Prevent Mold During Fermentation #AskWardee 074
- Lacto-Fermentation 101 Video Series
- Which Water is Best for Fermenting?
- Which Kind of Salt Should I Use for Fermenting?
- Do Lacto Ferments Contain Alcohol?
- Can I Use Alternative Sweeteners in Ferments?
- How to Tell if Your Kombucha is Moldy (And What to Do About It)
Helpful Links:
- How To Make Kombucha
- How To Make Kefir
- FREE Sourdough Starter Instructions
- FREE Fermenting Formulas Cheat Sheet
- Free Traditional Cooking Video Series
What arrangement do you use to keep your ferments spaced far enough apart? Do you break some rules and still get good results?
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Is that a pico de gallo recipe I spy in the picture? 🙂
I agree- what is in the jar in the picture. That looks delicious =]
Hi Emily and Sarah,
We don’t know. 🙂 It’s a photo we have permission to use and we’re not sure what is in it… it does look delicious, though!
~ Millie, TCS Customer Success Team
So how do you remedy raw milk kefir and kombucha cross contamination that has already happened?
Hi Amy,
You can’t save a finished ferment that’s been cross-contaminated. If it’s the culture, though, you could give it more time to get back on track through future ferments (spaced far apart).
Hope this helps. 🙂
~ Millie, TCS Customer Success Team
If your kefir is in a closed jar (plastic lid), then can you keep it closer to the continuous brew (cloth covered) kombucha so they can share the same warming mat.
That would be my question, too.
I was afraid of that! My ginger bug developed a scoby and it is probably 2 to 3 feet from my combucha. The combucha looks to be ok, but how do I know ? guess next taste will tell. The veggies I keep in the basement, there is not all that much space though, especially come cold season when all my plants have to move indoors again.
What does the scoby in your ginger bug look like? I’m working on a ginger bug right now and it’s milky white on the bottom. I had it near a milk kefir… Wondering if it’s from cross contamination or if it is normally whitish on bottom. This is my first ginger bug.
I was amused that Wardee had yeast in her cheese as I had the exact opposite issue. I was using wild microflora to ferment some simple cheese from raw dairy. My sourdough jar was above the sink where I was straining the cheese. Two weeks later my sourdough jar smelled cheesy?! Had to throw it out! I will never keep sourdough or any ferment near my sink again.
Thanks for this very useful information!
Much appreciated too! 🙂 Cool!
How long do the microbes last? I have fermenting corner that I continually switch up. Is a few hours between yogurt and Kombucha ok?
Hi Carol,
It is unknown and can vary widely how long the microbes can live in an area. Some cooks make it a rule to separate sourdough and cheesemaking by a day if not a few days.
It will take some trial and error to determine what’s a ‘safe’ time between your ferments.
~Vicki, TCS Customer Success Team
What if you’re using airlock lids like the ones from NourishedEssentials? They keep all air out while allowing CO2 to escape.
Hi, Anthony,
If you’re using an air-tight airlock, you can keep them closer together. 🙂
We are unfamiliar with these lids and if the part that screws on the jar is truly air-tight. Very few are. (Pickl-It is air-tight.)
~Peggy, TCS Customer Success Team
I’m working on a ginger bug right now and a sauerkraut and they’re both milky white on the bottom. I had them near a milk kefir… Wondering if it’s from cross contamination or if it is normally whitish on bottom. These are my first ginger bug and sauerkraut.
Hi, Alainya.
We recommend 5 feet between ferments so if they are closer it could be cross-contamination.
Is it a white substance or is the brine cloudy? Cloudy brine is not a problem. 🙂
~Danielle, TCS Customer Success Team
It’s a white substance on the bottom.
You might have a cross-contamination situation, then. It’s possible you’ll need to restart each ferment and keep them as far apart in your kitchen as you can — at least 5 feet.
Sonya, TCS Customer Success Team
What about when the ferments are in the fridge?
Hi, Chris,
Your ferments in the fridge will be fine next to each other if they have a good lid on them. The cooler temperatures slow the process down and you shouldn’t worry about them if they are sealed tight.
~Peggy, TCS Customer Success Team
Hi, you said ‘Never keep your sourdough starter near other ferments, especially cheese or other culturing dairy‘ but I can’t find out whether if your dairy (in my case yogurt) gets cross-contaminated by sourdough starter bacteria it makes it just a bit bitter or dangerous/ unsafe to eat (my latest batch if yogurt has a yeasty smell and looks yellow 2/3s down the jar)? Can I assume not dangerous/ unsafe as it just contains the sourdough starter bacteria but nothing ‘unsafe’ has occurred?
Many thanks
Michael
Hi, Michael.
It might not be unsafe, but it’s certainly not desirable. The cheese won’t work right, it won’t form the right curds.
Also the sourdough starter might smell bad for a few days until it adjusts or is moved away. I wouldn’t make bread with this starter.
~ Danielle, TCS Customer Success Team
Thanks so much Danielle!
Hello can tepache cross contaminate kombucha? And how do you fix cross contaminated kombucha?
I am a small batch brewer and sell kombucha so don’t want to take any risks. Thank you!
Hi, Isha: I’m happy to help! Yes, whenever two different ferments are placed too close together, there is a chance that one culture might contaminate the other. In the case of tepache, the “culture” is the healthy bacteria that is already present in the rind of the pineapple. These bacteria are likely different from those that are combined with the yeasts in your kombucha scoby. The tepache might not interfere with your kombucha, but it would be safest to keep them separated by a distance of at least six feet. If you think your kombucha is already altered, you might want to start fresh with a new scoby and keep it apart from other cultures. —Sonya, TCS Customer Success Team
So, I just started my kombucha and had my sourdough starter close by. Then I started my water kifer, still keeping my sourdough close. I then heard to keep them apart, but my kifer has a white film on it with small fuzzy dots. Looks like mold, is that from the sourdough starter? I have since moved my sourdough. Now I understand that water kefir and kombucha should also be kept apart, is that correct? If so are both of these no good? I really have not looked at my kombucha. I will move the water kefir now, but it may already be bad. 🙁
Thanks for all of your support!
Linda
Hi, Linda: I’m happy to help! I can’t confirm whether the white film and fuzzy dots on your water kefir are the result of keeping it too close to your sourdough starter, but it’s true that keeping cultures too close to one another causes cross-contamination and can render the cultures ineffective (which might mean that their strains become too weak to fight off unhealthy bacteria and molds). If possible, try to keep your cultures in different rooms — or at least six feet apart in the same room. (Yes, this includes water kefir and kombucha.) I think you should probably start your cultures again and keep them socially distanced. 🙂 I’m sorry about that! —Sonya, TCS Customer Success Team
Thank you for this helpful information. I quickly moved a new veg ferment (carrot) I started today as I had placed it beside my cauliflower ferment I started last week).
I have an established nukadoko vegetable bed that requires hand kneading/turning over on a daily basis. I scrub my hands before and after my tending duties, but the pickled smell lingers. I would like to get into sourdoughs, but should I do more sanitizing to avoid cross-culturing my baking endeavors?
Hi, Thomas.
Even if the smell lingers if you’re washing thoroughly and keeping your vegetables 5 feet from the sourdough you should not have any cross-contamination.
~Danielle, TCS Customer Success Team
What about when you are keeping a sourdough starter and milk kefir grains in the fridge? I stop and start both of these when I’m away from home.
Your ferments in the fridge will be fine next to each other if they have a good lid on them. The cooler temperatures slow the process down and you shouldn’t worry about them if they are sealed tight.
~Danielle, TCS Customer Success Team Lead
What other sorts of things should I watch out for in the presence of my ferments? I was starting kombucha from a kit and put it in my laundry room where it’s usually dark and would be far from my other ferments. But I wonder about laundry soap and dirty clothes being in the same room less than 5 ft from the jar. Is that a problem? If I put it near my fireplace, is the firewood or burning wood near it a problem? Thanks so much!
Hi, Sarah,
Your kombucha should be fine either in the laundry room or near the fireplace. The concern would be if it was near another ferment that is not the same type of ferment.
~Peggy, TCS Success Team
Thank you!!!
I have two different batches of water kefir grains. Do I need to keep them spaced 4-5′ apart from each other, or will they be okay if they are kept closer together on a warming mat?
Hi, Carol.
They can stay near each other. Ferments of the same “type” can stay close together. 🙂
~Makenzie, TCS Success Team
Are Dairy Kefir and Water Kefir different “types”?
Hi, Abby.
Yes, water and dairy kefir are different types and should be kept at least 5 feet apart. 🙂
~Makenzie, TCS Success Team