Harvest and Storage

Appears in
On Food and Cooking

By Harold McGee

Published 2004

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True “new” potatoes are immature tubers, harvested from green vines during the late spring and throughout the summer. They are moist and sweet, relatively low in starch, and perishable. Mature potatoes are harvested in the fall. The vines are killed by cutting or drying, and the tubers are left in the soil for several weeks to “cure” and toughen their skin. Potatoes can be stored in the dark for months, during which their flavor intensifies; slow enzyme action generates fatty, fruity, and flowery notes from cell-membrane lipids. The ideal storage temperature is 45–50°F/7–10°C. At warmer temperatures they may sprout or decay, and at colder temperatures their metabolism shifts in a complicated way that results in the breakdown of some starch to sugars. Makers of potato chips must “recondition” cold-stored potatoes at room temperature for several weeks to reduce their levels of glucose and fructose, which otherwise cause the chips to brown too rapidly and develop a bitter taste. Internal black spots in potatoes are essentially bruises, formed when an impact during handling damages cells and causes the browning enzymes to create dark complexes of the amino acid tyrosine (alkaloid formation and therefore bitterness often rise also).