Michigan State University Extension
Preserving Food Safely - 01600665
Light, heat and moisture facilitate enzymes in nuts and seeds causing rancidity. This makes it inappropriate to keep nuts for a long time in open bowls, clear glass jars or on sunny counter tops.
Any nuts or seeds kept for longer than a month should be stored in the freezer. Freeze chopped, ground, whole, roasted or spiced nuts in the shell or even in an unopened can. Nuts that are salted or spiced have a freezer storage life of six months, about half the time that plain nut meats can be stored in the freezer. Seeds also freeze for six months. Toasting and roasting diminish freezer storage life, and are best done when the nuts and seeds come out of the freezer, rather than before freezing; unless you intend to freeze them for only a few months. Unless freezer space is limited, it's best to freeze nuts in their shells, and crack them as needed. Use nuts and seeds directly from the freezer, without thawing first.