Is this mold or yeast on top of my pickles?


I used fresh washed cucumbers, grape leaves, dill fronds, and garlic all from my garden, plus peppercorns submerged in a brine consisting of 8 cups of water to 5 tbsp sea salt. I used a pickle pipe on the lid.
Started ferment on Aug 26, picture is on Aug 29.

Thanks, Tracy


Hi Tracy,

Definitely mold. Skim the top to remove mold. Wipe down edges with a clean towel. You can even remove leaves and replace with new ones. Then add new brine to the top and refrigerate. This should solve it. And the leaves have helped keep your cucumbers unaffected. It might seem like a short ferment but they will keep fermenting slowly in the fridge!



I want to understand pickle mold

colorful pickle mold

Hello, I have been fermenting for many years and I always wonder about the whole mold. I have heard some say just scrape it off and you'll be fine. I wondered your opinion. Hear is a pic of my odd pickle mold.

Thanks for your help.



Hi Kelly,

There are different kinds of mold and with those different concerns. The smaller white molds are okay and can be scraped off — once you get into pink and black molds you should throw it away. I also find that if it is a shredded sauerkraut scraping off mold will get you to a layer that has been anaerobic and safe from the mold, however, like in your pickles below that mold is on a cucumber that goes through the whole jar and I consider this to be more infected.

I hope that helps,


Fermented Tomatoes with white "mold"


I have two fermenting quart jars going on right now. One has habanero peppers and garlic, while the other has tomatoes, carrots and squash in it. They both have air locks on them. My question is, the one with tomatoes is getting like a white mold at the top and when the jar is tilted the white "mold?" is seen in the head space.
Is this normal or is this bad? Why only the one with vegetables. The first photo the jar is tilted on the second photo under comments to jar is level. Your opinions PLEASE.....


The good news is this is not mold. It is s kahm yeast and harmless. I would leave it alone until you are ready to put your ferment in the fridge. At that point spoon it off as best as you can and put the ferment in a new jar with as little air-space as possible—this should solve it. As far as why, well it happens and tomatoes and other sugar-filled vegetables are prone to it. Nothing you did.

Are Fermented Vegetables Cooked?

FermentWorks Fermented Carrots

Hi Kirsten,

Just found out about your business through OPB, and then saw your recipe for Carrot-Lime salad. I’m wondering if the fermenting process cooks the vegetables slightly or at all? I’m allergic to raw carrots, raw celery, and other very random raw foods, but can eat them all if they’ve been cooked (even a minute or two in a microwave eliminates this allergic enzyme or whatever it is…!) (Discovered a few years ago through my friend google, that this actually has a name: Oral Allergy Syndrome…) Up to this point I've just avoided any raw carrots, or fermented carrots, not wanting to deal with the itchy throat. Reading about your experience with fermentation, I was curious if you know anything about this (cooked vs. raw once fermented)? Thinking it might be like ceviche - acids cook the raw fish to create a finished dish of lime, fish, veggies…

Thanks for any thoughts you might have about this!



Dear Jana,

Wow there is a lot to learn here. I’ve spent most of the day looking through research papers and trying to get my arms around this. I’m guessing you are allergic to either birch or mugwort pollen, depending on what some of those other raw fruits and vegetables are. Either way as you probably learned from your friend Google the proteins in both of those veggies that are triggering your body’s allergic reaction are denatured by heat and likely also by your gastric juices. The question you raised, does lactic acid fermentation do the same thing, doesn’t appear to have been studied, at least I have yet to find it. The acidity in fermented carrots probably just approaches the pH 1.5-3.2 of our stomach, I’m not sure if there is a minimal pH level needed to foster enzymatic activity on the protein. In fact there seems to be a debate in the research in terms of what the pH likely is From what I can tell the thermal treatment unfolds the proteins, which causes them to not bind with the antibody response. The proteins I think at play here are PR-10 Bet v 1 proteins. The most promising thing I found is from a paper in Molecular Immunology 100 from last year that states “In addition, there are also numerous non-thermal processing methods such as e.g. hydrolysis, fermentation, UV-exposure and radiation influencing protein stability.” It later mentions Lactobacilli as having the capability to reduce IgE binding capacity.

So with all of that I think your hunch might be right. Would I would suggest is to ferment the carrots fully, meaning for a pint you might want to let them at least 3 weeks or maybe a month at room temperature. They will probably be a little soft but we would know that the lactic acid bacteria have had plenty of time to break things down, hopefully including the proteins that are fooling your body into thinking they are pollen and need to be dealt with in your mouth.

Our bodies are amazing aren’t they? Thank you so much for the question that I will continue to puzzle over. Please let us know if you decide to experiment and what the outcomes are. I do hope it works and you can once again enjoy carrots, celery and other veggies fermented.

Let me know if you have any questions about any of this and I can clarify or send you research I have found.



Fizzy Fermented Vegetables

Hi there,

I was wondering if you can help with a question I have. I have lacto fermented cucumbers once and I think the ferment went well however the pickles were so fizzy I couldn't eat them. This has also happened to me when I bought some fermented pickles from a shop. Again, I couldn't stomach the fizzyness. I am on day 3 of a batch of lacto fermented cucumbers and all is looking well with bubbles present but I just dont like the extreme fizzyness.

I have done some research but have found some conflicting information. Firstly, is the fizzyness safe? Secondly, is there any way to stop this from happening? Will there be a stage where the fizzyness settles down?

Thanks so much!



Hi Jessica,

I am assuming the fizziness is dissolved carbon dioxide in the brine, which were likely created by bacteria and maybe yeasts. In either case the fizziness is likely safe, though its making the pickles unpalatable for you which isn’t so good. I looked at some research on CO2 and brined cucumbers and they found that the amount of salt and the cucumber varieties both affected the amount of CO2 produced. The early CO2 (before the brine turns cloudy after a couple of days) seems to mostly come from the process of the brine saturating the cucumbers. After that it looks like the rest of the CO2 comes from the microbes. The researchers also found that the higher the salt concentration (they measured 4, 5.4 and 7%) the lower the total CO2 produced.

Taking this into account, perhaps you could lower the amount of fizz by either raising the salt in the brine or trying a different variety of pickling cucumber or both.


Feremented Rhubard Question

Hi Kirsten,

I made the lacto-fermented rhubarb fool recipe on your website in May with the hopes of preserving it for the winter. It worked well and tasted great. I left it in a half gallon jar in the fridge and recently moved it to the fridge door. When I looked at it again today, I noticed a slimy film on it. It doesn't smell bad, but it looks pretty bad. Do you have any ideas if it is salvageable?




Hi Carolyn,

I am happy to report that is just a small bit of surface yeast—called Kahm yeast. It is harmless. It can only grow where it has oxygen.

The best way to resolve this is to skim off the yeast one top and then put the rhubarb into a new smaller container. This will help control any population of yeast that is hanging out in the jar ready to go back to work when you remove it. More importantly a smaller jar will have less head space for oxygen to hang out and should solve the issue.

I hope that helps,


Fermenting Pepper Mash Floating over Brine

Pepper mash floating over brine

Hello Kirsten,

I just got your Fiery Ferments book (Love it!) and am just starting my first fermentation: the basic pepper mash. I started it yesterday and the mash does not seem to want to stay under the brine. I keep pressing it down with a large spoon, but the brine immediately settles at the bottom again. Is this ok? Is there anything I can do to keep the mash submerged? Thank you so much for writing such a wonderful, easy-to-understand book! I’m excited to try more ferments and eventually move on to the tempeh!




Hi Karen,

We do love to hear that people are out there using (and loving) our books. Thank you.

Your mash is behaving just as it should, and yes, it is nearly impossible to keep it under the brine. After a lot of different ways to try to solve this issue, I found the best is to leave the lid on tight —looks like yours is. Once (or twice if it is super active) open the lid slightly to burp it (release pressure) and then tighten right back up. Since CO2 is heavier it will push out the oxygen and rest on the top of your mash, shielding it. After you have burped it shake the jar to get the pulp and brine mixed up. It will separate again in a few hours but don’t worry there is no oxygen in there to cause it grief.

When it starts to slow down you will find that it will be less active and separate a much slower rate, and eventually not separate at all.

I hope that helps.

All the best,


Black Color on Beet Kvass

Hi Kirsten,

I ran across your page and thought I'd send this to you.

I'm new to fermenting, and decided to try kvass. I used a veggie peeler to get thin slices just as an experiment for texture. I tried this with 2 quart sized Mason jars. One batch turned out amazing. Best way to have beets IMO.

The other batch is why I'm contacting you. I used folded cabbage leaves to hold down the beet floaties. However the top of the cabbage leaf was exposed to air and developed a black mold of some sorts. It spread to the jar lid, the inside of the jar around the top, and looks like it leached down the side and went all the way down to the bottom. Take a look at the pics. Notice the mold I wiped away with a paper towel, and in the other pic how there is a thin black line streaking down the inside of the glass.

Is my batch contaminated??

I'm not comfortable getting sick over $2 worth of beets, so I'm cool with throwing it out and starting over. Just curious what it is and if it's harmful.

Lesson learned, put a rock in a baggie that keeps the cabbage submerged.




HI Kyle,

Nice to hear from you. Glad you are starting to ferment. I might be missing something that I can’t see in the photos but it looks to be that the black that you are seeing is actually oxidation which is quite common with beets and often happens near the top of a ferment — where the oxygen is.

I think that is all you have going on which isn’t going to make you sick. Just take off anything discolored. Also luckily with ferments you can’t get sick by something you can’t perceive—in other words bad ferments are pretty disgusting. ;-)

Definitely you are on the right track, keep everything submerged. I think the air-pockets that I see in the ferment would concern me more. Luckily nothing has moved in. Just press them out before storing.

I hope that helps,


Leaky Jars

Hi Kirsten,

I started making sauerkraut to sell at two farmer’s markets where they have created a terrific small business for me. However I have two major problems.

The first is mould in the jars. After the sauerkraut is decanted into the jars ready for sale, I notice that after a couple of weeks, in the fridge, they often have mould and taste awful. Sometimes if I catch them early I can scrape off the top inches and everything is fine underneath and we eat it ourselves. I can’t weigh the kraut down inside a jar for sale, so I was wondering if you had any tips there.

The second problem is that often people say they love my pickles, all thanks to your recipes, and would I post them down to them? But I can’t because my jars leak! No matter how much I tighten the twist off lids they still leak like mad. Which I don’t mind as it seems to be an outlet for fermenting gasses to escape and not build pressure up in the jar, but the customers don’t like my leaky jars either, especially the poor lady who had a very enthusiastic beet kraut bubble up in the boot of her car and left a big stain! She is not a fan any more... I’ve noticed that the sauerkraut from health food shops that is labelled raw and live do not have leaky jars but I can’t work out what they do to them. If you can cast any light there I would be profoundly grateful.

Thank you so much for launching us on this amazing fermenting journey,


I am glad to hear of your successes.

I am sorry for your trouble. I had to smile at the story of the beet kraut. We also had some overactive beets when we were in business, people weren’t happy when it made their bags look like a veggie murder scene.

Oxygen is getting in your jars. I suspect your lids aren’t airtight. If they were there is no way that the mold could grow, also this look like surface yeast to me not mold. The ferment covers itself with a layer of CO2 when there is no new oxygen getting in the jar. Since you are having a regular issue and the jars are leaking it tells me that the jar style you are using isn’t working.

When we taught in Chile a few months ago we bought jars that should have worked but they were not airtight and it caused a problem. The lids were a similar style to the one pictured. I would suggest finding a different jar source. When we were in business we used jars made for canning and they had a solid seal, even without the hot water bath. Some jars will only seal when boiled.

I hope that helps!


Blackened Red Onions

spoiled fermented onions


I attempted fermented red onions for the first time. The top half of them smelled, appear, and tasted great. The bottom half had pieces of red onion that had turned completely black. Very different smell. It was an off putting sour smell. Definitely not the same pleasant smell that was coming from the top portion of the jar. As I got closer to the bottom there was more black pieces and the smell was worse and stronger. Any ideas?


Hi there,

Nice to hear from you.

Somehow some oxygen must have gotten into the bottom of the ferment as it is unusual to see this happen from the bottom and not the top. I can’t say how that happened but it definitely sounds like you got spoilage due to oxygen. I trust you tossed it.



What Are The White Spots On My Pickles?


Hi Kirsten!

I have a question for you!

Can you tell me why this littles dots on my Pickles is normal? (Pictures are attached) They dont have that before..

The pickles was made the last summer so already 7 months in the fridge. 

Also, I find that often, my fermented vegetables are soft. Not crispy (pickles, greens beans, radish...) why ?

I always put a little bit of black tea in the final jar but help to keep their crispiness.

But I need your help! 



Hi Carolanne,
Oh dear, those do not look well. I believe this is some kind of fungus. This could happen if even one of the tops of the pickles was peeking out of the brine. That little bit of exposure acts as a vector. 
As far as soft ferments, more often than not that is because there is not enough salt in the brine. One of salt’s functions is to harden the pectin in the cell walls and this is what keeps things crispy. Tannins help but you need more salt to begin with. 
Cucumbers are especially needy in this regard. Of all the things I ferment cucumbers get the highest salt ratio. They just want to soften otherwise. You want to you a 5% brine. 
I hope that helps,

Should Fermented Rainbow Chard Turn Brown?


Hi Kirsten,

I recently tried fermenting some rainbow chard stems. They looked and tasted good while they were cementing, but after moving them to the fridge they are starting to turn brown at the tips. They have softened significantly, but don't smell or taste bad. I didn't weigh them down, so some were slightly poking out of the brine. I've attached some pictures. Are these safe to eat? 

Thanks for your help,


Hi Cassidy,

Unless they are somehow off-putting, smell, taste, mold etc. they are likely fine. If they are soft, that could be off-putting, but are safe if they taste fine. If they are mushy or slimy then they are no longer good.

The color and softness likely came from poking out of the brine. 



What Causes Blue Mold to Grow on Fermented Pickles in the Fridge?


Thanks for your website. I’ve fermented for over 10 years and until last year had delicious pickles. Last year the pickles in my old crock did not taste good, although the texture, firmness and looks were good. This year all four batches were delicious after they’d fermented on the counter., both green beans and cucumbers. I refrigerated them and they were good for a month. Then after being away for a month I found a blue mold on the surface of brine - on all 4 batches in the refrigerator. Same as that batch last year. They looked great, were firm but the taste is like medicine, like mold, after I'd carefully removed the mold. They are not good to eat. The mold is more leather-like than scum. I don’t think they are dangerous to eat, but sure not pleasant to eat. I’m tossing them. What went wrong? Should I invest in the German pickling jars? 


Hi Rebecca,

You are welcome, glad it helps. Goodness do you have some fine mold mats. 

It is good that you tossed them. Somehow you you you have gotten some tenacious little mold spores. The thing is they need oxygen to grow, sometimes when you repack a ferment from a crock there is just enough oxygen in the headspace to allow mold to grow. If the ferment is still a little bit active when you repack it you can actually let it sit out for a day with the lid on tight and as the lid bulges a bit then twist it slightly to burp it. This will push out the oxygen as the CO2 the ferment created is heavier an it will now blanket the pickles to keep them from growing mold.  As far as do you need different equipment? It is possible that there are some spores that have taken up residence in your older crock and they are what is giving you grief. Also older crocks sometimes have lead in the glazes whereas the newer ones don’t, so that might also be a reason for you to replace. With what? is personal preference the water trap crocks with the weights are nice, but you must be sure to keep the water full, otherwise they are just as prone to mold and other oxygen loving microbes as an open crock. Fermenting is jars is also a great option. 



What Color Should Fermented Garlic Have?


My name is Dalton and my fiancé and I have started our journey into the world of fermentation! That being said we started with the simple garlic honey ferment but I’m getting worried about the look the garlic seems to be taking on.

I’ve had some of the honey and I tried a garlic clove about 6 days ago and both were very good. But the farther along it gets the more the color is turning grey/dark and to me it looks strange. Is this ok to eat or does it mean the garlic is going rotten and we should start again?!

Thanks for any advice you can offer!


Hey Dalton,

Nice to hear from you—welcome to the fermentation journey. It is a good one. 

The color of the garlic will continue to get darker over time and that is perfectly normal. Go ahead and eat and enjoy your honey and your garlic. 



Why Would Fermented Green Tomatoes Appear Slimy?

Not Okay Okay


Thanks so much for all your advice and support.  I’m not super new to fermenting, but realize I’ve never done a cut, seedy vegetable before (mostly whole cukes, beets, cabbage etc), and notice something odd on this batch of green tomatoes. Some, but not all, of the cut surfaces seem to be acquiring a whitish, slimy looking (although not slimy feeling) bloom.  They have been under brine, in a crock, for about 3 weeks, and a few seeds have floated to the surface and caught mold, but I’ve discarded these and everything else seems to be fine.  One week ago they smelled and tasted pretty good - thought I’d let them go longer and now they don’t taste as good, and several have this... stuff.  Any thoughts?

Thanks in advance!


Hi Sara,

You are welcome. I am happy to help! However, I am afraid I won’t be much help on this one. It sounds like you did everything just right and last week all was well. Given they don’t feel slimy, just look slimy, I wonder if they just fermented too long and microbes that moved in were not yummy flavor makers. ou also said they don’t taste as good which to me is another indicator that the microbes shifted on you. This off course is all just an educated guess. I can tell you that in general cut seedy veggies are much quicker to cause problems. I have come to doing my cucumbers and green tomatoes whole (or chopped like relish) for this reason.  

As far as this batch, if they are not rotten (sounds like they aren’t) but aren’t pleasing there is not much you can do at this point. If you don’t like them don’t eat them, or make a relish with the ones that are okay and eat it soon. 

I hope that helps.



Is Sediment In Fermented Hot Sauce Okay?


Good evening,
I came across your page while worrying about my first ever batch of lacto fermented hot sauce. I've never fermented anything before, so i'd rather be on the safe than sorry side of foodborne illness. When starting, the ferment had tiny bubbles during the first week. The directions I followed stated to massage the peppers after a week, so I opened it up to do so. Other than that, I haven't touched it in 5 weeks. That 1 week mark was also the time, however, that it stopped producing bubbles. Do you mind just letting me know if it looks okay? No bad smell, just a lot of sediment/debris and no bubbles. These are red and green jalapenos along with onions and then spices. 
Thank you



Hello Casey,
Thanks for contacting us and sending photos. We have never heard of the massage at the 1 week technique and can’t think of why that would be suggested. Maybe the author had an issue with whole peppers not getting the brine inside them so they thought they should me massaged? Don’t know but I would suggest leaving that off your next batch process, you really should not need nor want to handle the ferments while they are fermenting.  Opening the lid also releases the protective CO2 layer that should be captured under the lid and water in your air lock. Is there water in your air lock on top of the lid?
On to good news - they look fine. That sediment you see is normal. I would suggest spooning some out and tasting. If you like then you might think about spooning all the vegetables into your blender and adding ¼ of the brine you think you will use and blend. Check the consistency and keep adding brine until you get to the sauciness you are imagining.
Let us know how it goes Casey.



What Causes The Milky Sediment At The Bottom Of My Ferment?


Three weeks ago I jumped into fermenting with both feet.  I fermented 10 jars of various vegetables.  3 weeks into it they are getting tasty.  Three jars were peppers from my garden.  About a week in I noticed two of the jars of peppers have this milky sediment on the bottom.  I used the same brine and added only garlic to all three.  All three still smell and taste great so I suspect that it’s safe but it looks nasty.  Do you have any idea what’s going on here?

Thanks for your help.



Hi Charles, 
Nice to hear from you and that you have thrown yourself into fermentation. 
The good news is this is perfectly normal, in fact all ferments have this sediment! It is actually a sign that everything has gone well. If you are curious look under the jars of Bubbies pickles in the grocery store and you will see the same sediment and the cloudy brine. 
Keep on fermenting!

What Is The White Film That Can Develop On Fermented Onions?



 I am so glad I came across your website. I have a batch of red onion ferment I am not sure is safe to try. I have quite a bit of experience with kimchi, but this is the first time I have tried fermenting onion. The recipe was just onion and salt, and the onions were supposed to give enough juice to keep them covered, but they did not and so the top layer was exposed to air. They were fermenting for about 2 weeks at about 19 degrees C. A layer of white film developed on top of the onions. It smells like fresh yeast. I have never had this issue before. Any idea what is it, and is the onion safe to consume? Thanks so much,Magdalena Denenberg 


Hello Magdalena,
Glad you found the site before you tossed the onions—they should be tasty. You are correct in that the film developed due to onions on that weren’t fully submerged under the brine. The is kahm yeast, harmless but not so tasty. You will want to scoop off this top layer and then the rest will be fine. I also suggest putting the good part in a smaller jar now that it is ready to refrigerate. Less air in the jar makes it less likely that you will see a film like this this. 
Happy to help. 
Enjoy the onions,

How Long Should Naked Kraut Ferment?


I followed the book “fermented vegetables” and it seemed my ferment was ready at five days. 
I didn’t want it too sour/“nasty” (my husband and a dear friend were skeptical at letting it sit too long) so i tasted it and jarred it up. it’s in the fridge. My first kraut. Naked kraut. 
Do you think I rushed it? 
We keep our house at 65F year round and i had this in a crock in my sewing room above our boiler room. 
Thank you!!!!


Hi there, 
Congratulations on your first Naked Kraut. Sorry for the slowish response. We have been traveling a lot. These look great. I am guessing you are enjoying them by now. As soon as the kraut smells pickley then it is technically done. As the time increases it just gets more sour. The only reason to let it go more is that it will continue to process the carbohydrates and “predigest” them for you. That said these younger ferments are super tasty and still good for you. 

How Much Brine Should Curried Cauliflower Have?


Hi Kirsten & Christopher,

I've been enjoying your book, "Fermented Vegetables."  I picked up a copy at a 

Story Publishing sale this summer.  I've made some great pickles and Edgy Vegetables. 

I'm writing because I'm having a problem with your Curried Cauliflower recipe.  I've followed the recipe and it's in a Gallon Jar with glass weights and a fermentation lid as you can see.  The problem is that it's not making much liquid.  I added about 1.75 teaspoons of salt when I made it and after 12 hours there was just maybe an inch of liquid.  It's definitely reduced in size a few inches.  I took out the contents and added another teaspoon of salt and put it back in the jar.  But I'm still not seeing much liquid after another 4 or 5 hours.

Can you help me?  Should I make a brine and add it?  The cauliflower is a head that I grew and picked a few days ago, so it's pretty fresh.




Hi Charley,

Hmmm. I wonder if you have more liquid now. Usually this is not an issue when the cauliflower is thinly sliced. It last oks like your cauliflower and veggies are all plenty small. A good massage or knee ding also help release the liquid. Problem is sometimes the veggies are just abnormally dry. I of course don’t know if that is what is going on but could be. 

You need just enough brine to keep things anaerobic with no air pockets. 

What to do from here is the question. If you now have enough—great. If not you could add a low salt water solution. Not my favorite but will save the batch. It sounds like you already have a bit of salt. The solution I’m thinking is 1 tablespoon per pint of water. I would say if you put in two teaspoons already then only make the brine with two teaspoons instead of the full tablespoon. 

Hope that helps.