Depending on the options you selected to ship your natto and how far away you are, it is possible for your natto to arrive at room temperature. Natto is a robust, “living” food product capable of withstanding a day or two at room temperature without significantly compromising quality, but it will begin a “second fermentation” if it warms to room temperature, progressively taking on a stronger flavor. For optimal flavor, we advise that you refrigerate your natto immediately upon arrival, and keep it refrigerated while you consume it.

Sometimes our boxes receive rough treatment during transit. Should you find any natto containers damaged upon arrival, please contact us at ayasculturekitchen@gmail.com. We are committed to your satisfaction and will promptly offer a refund or replace damaged natto at no additional cost.

Our natto has a unique taste that is savory, umami-rich, and mildly nutty.  It is well-loved in Japan and appreciated for its distinctiveness and health benefits.  Many Japanese eat it every day for breakfast.  

As it ages, it can become more pungent.  In this sense, it behaves somewhat like cheese. If you like mild natto, eat it within about 10 days of receiving it.  If you like a stronger-flavored natto, you can simply keep natto in your fridge longer before eating it.  Some people prefer 2-3 weeks of aging.  Natto’s flavor profile, especially after aging, can be an acquired taste for some people, but it is well-loved in Japan and appreciated for its distinctiveness and health benefits.

Fermented food is created through a controlled process involving beneficial microorganisms like bacteria or yeast, which transform the food into a more digestible and flavorful form, often with added health benefits.

It is possible for “bad bacteria” to take hold in any food product.  Some bacteria can produce toxins that are unsafe for people to eat.  If a product smells wrong to you it is best to avoid eating it.

Fermented foods are generally good for your gut health. They contain probiotics, which are beneficial bacteria that help maintain a healthy balance in your digestive system. Consuming fermented foods can improve digestion, boost the immune system, and contribute to overall well-being.

The effects of probiotics are enhanced when they are consumed with prebiotics. Prebiotics are a type of non-digestible fiber found in certain fruits, vegetables, and whole grains that act as food for the probiotics. By providing the probiotics with the nutrients they need to thrive, prebiotics help the probiotics work more effectively and promote a healthier gut environment. Combining probiotics and prebiotics in your diet can lead to improved digestion and overall well-being.

Natto should be stored in the refrigerator, preferably at temperatures between 35°F and 40°F (2°C and 4°C). Keeping it in its original packaging or a sealed container will help maintain its freshness and prevent the absorption of other odors in the fridge.

After a month or more, you may notice natto becomes “gritty” or sandy.  This is due to the natural formation of crystals.  While these do not pose a health hazard, they are unpalatable, and such natto should be discarded.

Yes, you can freeze natto to extend its shelf life. To freeze natto, place it in an airtight container or a resealable plastic bag, making sure to remove air as much air as possible. Frozen natto can last for several months, but it’s best to consume it within 3-4 months for optimal quality. When you’re ready to eat the natto, thaw it in the refrigerator for a few hours or overnight before serving.

While natto can be frozen, natto generally tastes better and has more active bacteria when it is fresh and never frozen. Freezing will slightly alter the texture and taste, making it slightly “grainy”.  For the best natto experience, it’s recommended to consume it fresh when possible.

Natto has been found in studies to act as a blood thinner, providing many beneficial health effects. If you are already taking blood thinning medication, you may wish to consult with your doctor before regularly consuming natto.

After fermentating our natto, Aya’s Culture Kitchen refrigerates natto for a minimum of one day.  During this initial refrigeration period, important proteins and enzymes are formed, which help give natto its unique taste.  Brand new natto that has been refrigerated for only one day has the mildest taste.  While some people prefer this taste, others say that natto tastes best after about two to three weeks of refrigeration from the production date, allowing its natural flavors deepen.  We encourage you to experiment with our natto to decide the aging period you like best.

There are in fact some huge sustainability element to our business. Almost all natto sold in the US until now was made in Japan, frozen (using energy) and shipped 6,000 to the US (consuming energy). In addition, a big portion of the dried soybeans used for making natto in Japan are actually imported to Japan from the U.S, meaning that those soybeans have taken a 12,000 mile round-trip. So, for starters we are eliminating that wasted energy.

As to the containers themselves, while we are not permitted to bring outside containers back into our kitchen as we cannot allow any possibility of contamination, our customers are telling us they reuse these containers for food storage. That said, if you have any other ideas, please share them with us! 

The shelf life of natto can vary depending on a variety of factors, including the consistency of the temperatures in your fridge. Over time it will take on a stronger flavor. Some people prefer the mild flavor of “fresh” natto, while others prefer natto that has aged for several weeks. 

Eventually natto will develop white, sand-like granules. These are amino acid crystals known as tyrosine. These crystals are not harmful to humans, but they can be unappetizing, with a “gritty” or “sandy” texture. When you notice these crystals, it is time to discard it.  This image below shows what this can look like:

For shipments within the U.S., our nattos are available in quantities of a variety of pack sizes, currently from 4 to 24 packs.  For customers in the New England area, we offer a flexible purchasing option at our farmstand. There you can buy any quantity of natto, starting with just one pack. Additionally, we’re actively working on making our nattos available in Japanese and Asian supermarkets across the U.S. We’re committed to keeping our customers updated on this progress and hope to provide more versatile purchasing options in the future.

During the hot summer months, cold packs may melt during shipping, and your natto might arrive warm. This is totally okay! Natto is typically fermented at around 100°F and can handle heat quite well.

As long as it’s sticky and smells like natto, it’s safe to eat (though we recommend chilling it before enjoying—it’s much tastier that way!).

If you notice any sour or bitter smells, that’s a sign it may have spoiled—please don’t eat it and reach out to us right away.