Do Potatoes Go Bad When They Freeze?

The potato (Solanum tuberosum), that versatile tuber with culinary uses that could easily fill a cookbook, from mashed mounds of potatoes and French fries to potato soup, is a staple in many a home. While potatoes are often grown as annuals, they are perennials that thrive in United States Department of Agriculture plant hardiness zones 1 through 7. Whether you are growing or storing potatoes, do not allow them to freeze before you have taken proper precautions.

After harvest, you can store potatoes in a cool, dry place, like a cellar or a garage, as long as the temperature remains at least 40 degrees Fahrenheit. Store potatoes, unwashed in a dry area that does not freeze; washing potatoes can shorten the tuber lifespan during storage. If potatoes freeze during storage, throw them out while they are still frozen to avoid a soupy mess. When potatoes freeze, the water in them separate from the starch, which makes them watery.

Uncooked potatoes are not meant to be stored in the refrigerator. Cold temperatures cause some varieties of potatoes to quickly convert starch into sugar and can cause purple discoloration inside the potato. Cold potatoes "fry dark," which means the sugars in cold potatoes caramelize when fried giving a burnt appearance, although they are safe to eat. If you boil, bake or microwave potatoes that were refrigerated raw, they won't turn dark and you most likely will not notice the sweeter flavor.

You can freeze potatoes if you prepare them first. After harvest, scrub the potatoes, leaving the skins intact. Potatoes require blanching before freezing, which means placing them in boiling water for a specific amount of time. Blanching time depends on the size of potato chunks. For chunks smaller than 1 1/2 inches, blanch for 4 to 6 minutes and 8 to 10 minutes for chunks larger than 1 1/2 inches. This heating of the potatoes prevents the conversion of starch to sugar during freezing. Once potatoes cool, drain them and pack them for freezing.

Potatoes growing in the garden cannot withstand freezing temperatures and must be protected from the cold. If freezing temperatures are expected, cover 3- to 4-inch plants with soil and protect larger plants by covering them with freeze protection fabric. Once weather warms remove the soil or covering. Underground tubers can remain in the soil and dug as needed if covered well to protect them from sun; harvest all tubers before the first frost.