How to tell if cashews are rotten? They may have a moldy or off-odor surface if they’re not fresh. This can be a sign that the nuts are overly old or have been stored in high temperatures for an extended period. Remember, cashews are known for their rich, creamy flavor, and when they’re fresh, they’re never bitter. However, once they’re gone, the smell will be too, and this is an indication that they’ve gone rancid.
Another sign that your cashews are rotten is mold or other organic growth on the shells.