Jar rot can easily taint a quality batch of cannabis and slip through lab testing since it generally occurs after the flower is tested. Jar rot develops when fresh flower is improperly dried and cured or is put into a jar with insufficient air circulation and excess humidity, not allowing the product to breathe as it dries out or cures.
Jar rot is the same fast-growing, light gray mold found on strawberries that are left in the refrigerator for too long. If jar rot is fresh, it will smell slightly damp and a grey fuzzy mold will be present. If flower has jar rot and then dries out, fungus can be seen faintly, but will not have an odor.
Grower's Tip: If you're looking to avoid jar rot, be sure to make sure your flower is properly dried before you cure it. Then you can "burp" your dried flower by opening the container and rotating it once a day. With proper drying, burping, and rotating, you'll avoid jar rot while curing your flower.