If you suspect your walnuts have turned, there are a few easy ways to gauge their freshness. Give them a press; fresh walnuts will be firm and not at all softened.

Nuts can be stored for a month in the refrigerator, but the freezer is best for the long term. The cold helps prevent nuts from turning rancid, which would affect their flavor.

Walnuts also have the potential to increase HDL cholesterol, known as “good” cholesterol, said Abhilasha V, chief clinical ...