Being mostly made of salt, I often used soy sauce well beyond (as in "two years and more") its expiration date without ever having a problem. Is that a bad idea, and did I actually take some health risks doing so?
Still tasty implicitly says that the sauce stays indefinitely technically edible. The expiration date is only for quality purposes. I think the sauce probably doesn't have an expiration date but rather a "Best By" or "Best if Used By" date.
- Storage time shown is for best quality only — after that, the sauce's texture, color or flavor may change, but in most cases, it will still be safe to consume if it has been stored properly.
- If sauce develops an off odor, flavor or appearance, it should be discarded for quality purposes.
It depends. Are you talking tamari, shoyu or western soy sauce? Good tamari will improve with age (which is why I buy it in 5gal quantities even though I use far less than a gal/year). The same is probably true of shoyu as well, but westeren soy sauce has additional ingredients which may affect shelf life.