Lacto-Fermentation Problems Troubleshooting (FAQ)

You have just completed a lacto-fermentation (vegetable fermentation), and you are wondering if everything is going well in your jar? Do you think you might have a problem?

First of all, don’t panic! Fermented vegetables are very safe. Thanks to the acidity created by good bacteria, no bad bacteria can develop.

There is no risk of botulism, salmonella, or other bacteria. In fact, fermentation is safer than raw vegetables and canned food!

Believe us, you WILL KNOW it if your lacto-fermentation has failed: disgusting smells, hairy mould, spectacular colours, etc.

Read on to discover the different phenomena that can occur in your jar. While some situations are normal, others may indicate a problem.

If you were to remember only one piece of advice, this is it:

When in doubt, trust your senses. If it smells or tastes bad, throw it out!

Jump directly to your issue:

Mould and yeasts

Colour change



Textures and taste

Mould and Yeast in Fermentation

Is the White Film on the Surface Normal?

If there is a whitish layer on the surface of your fermented vegetables jar, it is probably a biofilm that is called “Kham yeast”. Don’t worry, it’s safe!

Microorganisms can form a delicate and almost odourless white biofilm. This film covers all or part of the surface of the liquid in your fermentation jar.

Kham yeasts

This biofilm is harmless to health. However, it can alter the texture and taste of vegetables. It is, therefore, better to remove this film with a spoon and place the jar in the fridge.

Tip: Keeping the fermentation in a cool place can prevent or reduce the development of Kham yeast.

What if There Is Mould on My Cultured Vegetables?

Mould looks powdery and almost “hairy”. It is often blue, green, grey, black, or sometimes white.

Biofilm (kham yeast) on a lacto-fermentation

If the mould has settled in your fermentation jar, unfortunately, you must throw it away and start over.

If there is mould, that means that your vegetables have been in contact with oxygen. This is something we want to avoid! Next time follow our complete lacto-fermentation guide.

We do not recommend consuming food with mould.

However, many fermentation specialists remove the mouldy part, especially when it is small (and no longer covered by brine), and eat the vegetables if they have a good smell and texture.

Change of Colour

Why Did My Fermented Garlic Turn Blue or Green?

Garlic sometimes turns blue or green during fermentation. This is normal and safe!

This colour change is due to a substance found in garlic that reacts with the acid of the fermentation. This phenomenon does not affect the taste or texture of your fermented garlic. It is all good, you can eat it!

To learn more, read Why Did My Fermented Garlic Turn Blue or Green?

The Colour of My Vegetables Changed During Fermentation. Is That Normal?

Yes, the colour of vegetables often becomes duller during fermentation. Some vegetables, such as beets or red cabbage, can colour the rest of the jar.

For example, we use a small beet to colour turnips in our Lebanese fermented pink turnips recipe!

Jar of Pink Turnip Pickles

However, if there is a dramatic colour change, this is not good. It’s extremely rare, but if, for example, your carrots turn black or your cauliflowers turn bright orange, and there’s no logical explanation, trust your common sense. Throw them out!


What Should I Do if the Brine Has Evaporated?

If the brine level has gone down and your vegetables are exposed to air, you can either add brine (if it is still early in the process) or leave it alone (later on).

If it has been less than 3 days since fermentation started, you can open the jar and cover it with new brine. Put your weight back in place and make sure the vegetables are covered.

If it has been more than 3 days since the vegetables have been fermenting, and everything is tightly closed, the vegetables are probably now covered with a “cap” of CO₂. In this case, bad bacteria will not be able to grow. Better to leave the jar alone!

Having doubts? Place in the fridge, and let your jar mature in a cool place!

Learn more about salt and brine in lacto-fermentation.

Why Is My Brine Is Cloudy?

It’s perfectly normal for your fermented vegetables brine to become slightly opaque and whitish. There is no danger!

Some vegetables, like beans or pickles, will whiten the brine in a few days. This means that the good bacteria are doing their job!

Cloudy brine and lacto-fermentation

The floating particles will eventually settle in the bottom of the jar, and the brine should lighten slightly over time. White deposits at the bottom of the jar are also normal.

Don’t worry, in lacto-fermentation, everything that occurs below the surface is safe.

Why Is My Brine Slimy?

Fermented vegetables brines can become sticky or slimy, but this phenomenon is safe. It is caused by harmless bacteria. Possible causes of slimy fermented vegetables:

  • Fermentation temperature too low or too high
  • An external source of bacteria (whey, etc.)
  • Very sweet vegetables (ex: beets)

Tip: If you don’t like the texture of your cultured vegetables, you can add it to dishes such as salads, stir-fries, or soups.

Lacto-Fermentation Odours

My Fermented Vegetables Smells Like Sulfur. Is This Normal?

This can happen. Some fermented vegetables may smell like sulfur after fermentation, but they are still delicious and safe to eat.

Onions, radishes, and cruciferous vegetables (cabbage, cauliflower, etc.) may smell of sulfur. This smell is often noticeable within the first few days of fermentation but disappears with prolonged fermentation.

It’s like the smell of a strong cheese… You will love it one day ;)

My Jar Smells of Decay. Is This Normal?

No, lacto-fermentation should not smell like decaying vegetables. If you are unable to hold the jar under your nose because of the smell, throw it away! Trust your common sense.

Vegetable Texture and Salt

My Vegetables Have Gone Soft. Is This Normal?

Yes, vegetables tend to soften during fermentation. Don’t worry, they are still very tasty.

Several factors influence texture:

  • Fermentation time
  • Concentration of salt
  • Temperature
  • Kind of vegetables used

Tip: Add fermented vegetables that have gone too soft to sauces, soups, or chowders.

To learn more about the factors that affect the texture, read Preserving Vegetables With Fermentation.

What to Do if My Fermented Vegetables Are Too Salty?

Did you drop the salt shaker in your sauerkraut recipe (or any other fermentation)? The easiest way to remove it is to rinse immediately or add more vegetables until it tastes good.

The level of salt does not decrease during fermentation. If it is too salty on day 1, it will be just as salty on day 30.

If you realize that your fermentation is too salty when you eat it, you can rinse it out (but you will lose lots of flavour and nutrients) or start a new one by adding the old one to the same or a greater quantity of fresh vegetables.

Follow the normal procedure for making fermented vegetables and let it ferment for at least a week.

A final option is to consume your extra salty fermentation by adding it to other dishes that have little (or no) salt.

Click here to learn more about salt in lacto-fermentation.

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