How to Store Natto (Explained!)

Natto is one of those foods that gets a strong reaction among those who have tasted it.

Some absolutely love it, and others have declared it stinky and inedible.

Regardless of one’s preference, it’s true that natto is an ancient Japanese dish and a real powerhouse among fermented foods.

However, if you’re planning to purchase and try natto, you might wonder how to store natto properly.

Because natto is made from fermented soybeans, it has special storage needs.

Natto needs a colder environment to prevent over-ripening and change in flavor. It can be stored in the fridge or freezer and heated when necessary.

Read on to learn more.

how to store natto

Does Natto Expire?

One of the most critical questions natto novices may ask is – can natto go bad?

When you purchase natto from an Asian supermarket or an online store, you’ll notice that it typically has the “best by” stamp.

Usually, this deadline is six to seven weeks from production, but it’s not considered set in stone.

That’s because, as a fermented food, natto doesn’t “go bad” as other foods do.

Therefore, the “best by” indicator merely tells you how long natto will have the best flavor so you can enjoy it thoroughly.

Regardless of how you store it, natto will continue to ferment, and its taste will change too.

A sign of spoiled natto are tiny white specks on the surface.

This isn’t mold but amino acid crystals, which are safe for consumption but taste terrible.

So essentially, the longer you store natto, the worse it tastes. And because you’re unlikely to eat it past a certain point, it does expire.

Does Natto Need to Be Refrigerated?

The answer is yes – you should refrigerate natto.

That’s how the fermentation process slows down, and the off flavors develop more slowly.

Plus, if you’ve purchased natto in a glass jar, keeping it in the fridge keeps it safe.

How Long Is Natto Good in the Refrigerator?

Learning how to store natto correctly is essential; otherwise, the content might go to waste before you can consume it all.

You can keep natto in the refrigerator for up to three months, though it’s probably going to have the best flavor for about a week after you open the jar or the box.

If you don’t eat all of your natto within a week, the changes in flavor will be gradual, and you’ll notice the unique ammonia-like smell associated with natto and increase in strength.

Remember that natto is up to 60% moisture, as the soybeans are soaked and pressure cooked before being mixed with bacterial culture.

Therefore, natto needs to be in an air-tight container, even in the fridge, to slow down the “spoilage.”

Can Natto Be Frozen?

You can absolutely freeze natto, though some enthusiasts argue against it.

The reason why some may discourage freezing natto is not that it’s unsafe but because natto’s taste and nutritional richness may diminish.

The process of freezing and thawing could disrupt the cells of the Subtilis bacteria responsible for natto fermentation.

Still, if you have more natto than you can eat in a reasonable amount of time, freezing it is a viable option.

How Long Can You Keep Natto in the Freezer?

You can keep natto in the freezer for up to three months, but there are no guarantees the flavor won’t change sooner.

Natto is not the type of food that can be stored for too long and should be consumed as soon as possible.

But if you have natto in your freezer, you can thaw it, microwave it for 30 seconds, and hope it still tastes good.

Once you thaw it, ensure to eat natto within one week.

What’s the Best Way to Store Natto?

Again, once you open the box, bag, or jar of natto, make sure to put it in the fridge and consume it within a week or 10 days.

However, you can try a few tips to ensure the natto flavor doesn’t change too much after the initial week.

Freeze Before Opening

One of the ways you can extend how long you can store natto in the freezer is to put the unopened container straight into the freezer.

If you have a few packs of natto and know you won’t eat all of it within a week, place them in the freezer as soon as you bring them home from the store.

Season Natto

Many people love natto because it mixes well with different ingredients and seasonings.

However, if your goal is to minimize the changes in flavor as natto sits in the refrigerator, consider adding some onions, scallions, various sauces, and even mustard.

Put Natto in Air-Tight Containers

If you’ve purchased a large bag of natto, you’ll probably need to split it into smaller storage containers.

Reusable plastic bags or Tupperware are great options, but you need to be sure to let out any extra air.

If possible, consider using a vacuum packaging device or at least pressing the plastic bag until you get the air out as much as possible.

It’s also essential to ensure the containers are clean before using them for natto, as the contamination will affect the taste and lead to mold growth.

Only Purchase Single Portions of Natto

This might not be a how-to store natto tip, but it is something to consider.

Some stores sell natto in a single serving size — around three tablespoons — with a packet of mustard and fish sauce.

Eating fresh natto, mixed with these ingredients, is the go-to choice for many, as you get most of the gooiness and authentic flavor.

However, once you store natto in the fridge or freezer, you risk letting it go bad and eventually throwing it out.

However, storing larger quantities of natto makes sense if you love mixing it with other food like rice or noodles or if you enjoy having natto toast in the morning.

In Summary

Some natto manufacturers produce natto flavored with turmeric and other seasonings, but many only love natto in its original form.

So, whether you eat it with sushi or salmon or use it to make an omelet, it’s essential to learn how to properly store natto.

Refrigeration is a must if you want to enjoy the authentic flavor for a week, but freezing is also an option.

Remember not to leave natto at room temperature as the fermentation will ruin the flavor in record time. Instead, enjoy natto fresh, and store it in air-tight containers.