Is Mustard Fermented? (Not What You Think)

As a popular condiment, mustard is subjected to many food-related queries whether from food critics, skeptics, or just about every other person with questions.

One of these questions is whether mustard is to be considered a fermented product. So what’s the answer really? Here’s what I learned!

Is Mustard Fermented?

Mustard, as a whole, is not a fermented product. Although vinegar, a fermented product, is added in with the other ingredients, the whole mixture is not fermented after being combined. Vinegar also happens to be replaceable and when substituted, mustard does not contain a fermented ingredient. 

So why do other people consider it fermented? Why do others want it fermented? Keep reading for the answers!

Is All Mustard Fermented?

No, not all mustard is fermented. Though there are certain types of mustard-like Kasundi that are fermented on purpose to acquire a certain taste, most prepared mustards are not.

Take for example yellow mustard, Dijon, Dusseldorf, and hot mustard. These do not undergo any process of fermentation but are simply mixed together, processed, and bottled for consumption.

Some may argue that mustards contain vinegar which is a fermented ingredient. Yes, they do. However, only the vinegar itself is fermented, the mustard mixture is not.

Can All Mustard Be Fermented?

Not all mustards can be fermented. But some can.

Store-bought mustard, not so much. But homemade mustards that start from scratch can certainly be fermented.

In fact, several people have their own recipes for fermented mustard and seem to prefer it to store-bought mustards.

Most recipes I’ve seen almost always involve a brine, some sort of starter culture, or a former mix of previously prepared lacto-fermentation, mixed in with mustard seeds and left to ferment.

In the simplest sense, all you need to ferment mustard are mustard seeds, salt, and water. However, a culture starter is usually needed in most homemade recipes in order to speed up the time of fermentation.

Fermented mustard is deeply acidic and has a complex flavor. It is also one of the easiest fermented foods to make because you just need to mix the ingredients together and let the bacteria do the work for you.

Does Vinegar In Prepared Mustards Stop Fermentation?

Is Mustard Fermented?

This is where the debate comes in because even though vinegar is a fermented product, its acidity can affect the fermentation process.

Introducing vinegar at an early stage in the fermenting process can slow down the fermentation and limit the growth of all the good lactic acid bacteria.

Thus, if vinegar is mixed at the same time with all other ingredients of the mustard, fermentation is slowed down.

However, if you make homemade fermented mustard, no vinegar is needed to achieve fermentation. You just need to ferment the seeds on their own with brine, or any culture starter of your choosing.

Vinegar and other flavorings or spices can be mixed in after the fermentation process has been completed and the mustard has rested with the good bacteria.

What Is Lacto-Fermented Mustard?

Lacto-fermented mustard is mustard that has undergone lacto-fermentation.

Lacto-fermentation is the process where lactic acid is produced as naturally occurring bacteria feed on the sugar and starch present in food.

This process used to be popular in times when keeping food without refrigerators was important as it is very good for food preservation.

Preferred by many, lacto-fermentation produces healthy gut bacteria that aid in digestion and help reduce flu and colds.

What Is Fermented Mustard Good On?

Just like regular mustard, fermented mustard is good on anything you want it paired with. Use it as you would your regular mustard and the taste is elevated.

Its sour, savory, and zippy taste will complement almost anything prepared mustard would be good on.

If you want to learn more about mustard, you can see our related posts on whether mustard is kosher, if mustard is halal, and if mustard is dairy-free.


Mustard can be fermented if you want it to be. You just have to make your own and oversee the fermentation process.

Additionally, some people prefer fermented mustard to prepared mustard. This is down to individual preference.

Moreover, mustard in its own basic state is not fermented by any means. The addition of a fermented product to other recipes does not make the product fermented as a whole.

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