Long-Term Storage for Sunflower Seeds

Temperature

• The temperature for keeping sunflower seeds should be below 70 degrees Fahrenheit. Above this temperature, the seeds should be transferred to the refrigerator or freezer for storage, as recommended by Michael T. Murray in "The Condensed Encyclopedia of Healing Foods." Low temperatures are required for long-term storage of sunflower seeds because elevated temperatures trigger the sprouting response in the seeds, according to "Handbook of Cereal Science and Technology" by Karel Kulp.

Humidity

• Kulp notes that high moisture levels, coupled with temperatures above 70 degrees Fahrenheit, can cause the seeds to sprout, but the moisture level also plays a role in the development of mold on the seeds. Differing humidity levels allow for the proliferation of various types of molds, based on the conditions the strain causing the mold reproduces best at. For sunflower seeds, dry storage at humidity levels below 65 percent is ideal. The freezer will provide such conditions in the home for the long-term storage of the seeds.

Container

• Rancidity occurs from the oils in the seeds coming into contact with air and oxidizing. This is especially important for hulled seeds without the protective exterior shell. To avoid this, keep your sunflower seeds in an airtight container and leave them whole. The hulls on the seeds, though porous, are another barrier to oxygen and moisture, both of which can ruin the seeds. Hulled seeds have a much shorter shelf life, and they should be sealed in an airtight container and frozen for best results.

Shelf Life

• Kept properly, sunflower seeds will remain safe to eat for more than one year if they are frozen. Compare this time to the two- to 12-month shelf life sunflower seeds have at room temperature or the six- to 12-month shelf life when refrigerated, according to "The Illustrated Cook's Book of Ingredients." The storage time for sunflower seeds at room temperature greatly depends on your climate and how warm you keep the storage area. In humid, warm areas, keep sunflower seeds in the refrigerator or freezer to preserve their freshness.