The Reason Soy Sauce Never Expires

Just about everyone has a bottle of soy sauce in their pantry, but if you don't reach for it very often, you might find yourself wondering just how long it's been there. Luckily, you don't really have to worry about ruining your fried rice or sushi with expired soy sauce, because it lasts a long time, even stuffed in the back of a cupboard. And if you have an unopened bottle of soy sauce, you don't have to worry about it expiring at all.

According to KitchenSanity, a sealed, unopened bottle of soy sauce won't expire or go bad as long as you store it correctly. The best way to make sure your soy sauce lasts is to keep it in a cool, dry place, like a cupboard or pantry. Also, keep it away from heat sources, like sunlight, your oven, and the microwave, because they'll make it easier for bacteria to grow.

So what is it about soy sauce that makes it last for so long? According to the Kikkoman company website, soy sauce is made with just four ingredients: soybeans, wheat, salt, and water. Soybeans are the primary ingredient, and wheat helps give the sauce its scent and a little sweetness. Salt is the key to making the sauce last a long time; it's dissolved in water, which creates a brine that controls bacterial growth during the fermentation process, and also helps preserve the finished soy sauce and prevent it from going bad. Well Fed also notes that the high amount of salt in soy sauce makes it difficult for bacteria to grow, which is why it can last so long without expiring.

Unopened soy sauce may never really go bad, but once you open the bottle, it's a slightly different story. It'll still take a long time to expire, but eventually, it'll be past its prime. According to Kikkoman's website, their soy sauce will last a few months after it's been opened. They also recommend storing the opened bottle in the fridge; this will make it last longer than storing it in your pantry, as long as the sauce doesn't get mixed with water or any other contaminants.

However, according to KitchenSanity, an opened bottle of soy sauce stored in the fridge might be able to last for up to two years. The main problem isn't really the sauce going bad — it's the quality of the flavor declining. Even though the sauce might still be good even after a year or more, for the best flavor, you probably need to use it up within about six months. It won't quite last forever, but you don't have to worry about using all of it right away.