Storing Potatoes

The first thing to remember about a potato is it's a living and breathing organism. Thus if you warm it up it will grow. If you seal it in a plastic bag it will suffocate. If they are diseased they will spoil. If its kept too cold it will freeze, and if its in too much light it will green up. They should be kept in a cool dry area, away from light. A cellar is ideal. On the farm we store the potatoes in computer temperature and humidity controlled cellars with air circulating though the potatoes. Thus we can store the potatoes for long periods.

Before storing spuds, look them over and use any bruised, cut or damaged ones first. Since dampness can cause decay, it is best not to wash spuds before storing. Store potatoes in a cool, dark and well ventilated place. They will keep about a one to two weeks at room temperature and for several weeks at 45 to 50 degrees Fahrenheit. New potatoes (fresh from harvest) will always store longer. Potatoes that are purchased frozed have been to a quick-vacuum partial dehydration and instant freezing. Potatoes that are frost-bitten are watery and have a black ring under the skin when cut in cross sections.

However, refrigerator temperatures are too low, which converts the potato's starch into sugar, resulting in a sweet taste. The extra sugar also causes potatoes to darken prematurely while frying. (This process can sometimes be reversed by storing the potatoes at room temperature for a week to 10 days.) Also once a potato has been kept too cold, the mealliness can never be returned to it. If potatoes have green patches, cut them off, as they have been exposed too long to direct lighting and will have a faintly bitter taste. The rest of the potato will taste fine.


Potato Dormancy

Length of Dormancy of some common Varieties stored at three temperatures

Variety Length of Dormancy at 40 F Length of Dormancy at 45 F Length of Dormancy at 50 F
Ranger Russet N/A 95 - 110 days 65 - 75 days
Shepody N/A 95 - 110 days 65 - 75 days
Russet Norkotah 150 - 200 days 115 - 125 days 80 - 90 days
Russet Burbank 160 - 210 days 150 - 160 days 100 - 150 days
Russet Nugget 160 - 210 days 90 - 120 days 60 - 90 days

Note: Conditions at harvest, vigor of the plant during the growing season and how fast the potato crop was cooled down in the fall can greatly affect how long a potato will store without sprouting problems. Also, the longer a potato has been stored, the quicker it will sprout once warmed up if no sprout inhibitor has been applied. Sprout inhibitors prolong the storage dormancy period and work best if potatoes are kept cool. Although a small sprout can start in days to weeks once a tuber has been warmed above 60 F. Storage tubers will keep about a week at room temperature and for several weeks at 45 to 50 F. They will keep longer if from a new crop. Its best not to wash potatoes before storing.



Other loses in storage:

Shrink. Potatoes if stored at high humidity will lose 7 - 10 % of their weight over a three month period. If stored at lower humidities potato tubers will lose more of their weight - up to 20 % at times.

Diseases. Most diseases affecting potatoes stop growing around 40 F to 42 F. Temperatures above this can result in losses. If the tubers are clean and unbruised to begin with no problems will occur. So it is important to buy disease free potatoes and handle them with care.

Greening. Potatoes stored in light conditions will turn green with in a week.