Sweet Potato

Sweet potato: freshness and ripeness guide

Sweet potatoes do not ripen further after harvest the way soft fruit does; they are cured in warmth and humidity for several days after lifting, which heals the skin and converts some of the starch to sugar, so the roots in the store bin are already at their sweetest and only need to be chosen well and stored properly. Pick roots that feel firm and heavy for their size, with smooth, taut skin, even colour, and ends that taper rather than collapse. Shallow scuffs and small surface blemishes are cosmetic, but pass over any root that is bruised, cracked, cut, or already soft, since damaged tissue is where decay begins. There is nothing to wait for at home — a sound sweet potato is ready to cook the day it is bought.

To keep sweet potatoes for later in the week or beyond, store them loose in a cool, dark, well-ventilated spot — a pantry or unheated cupboard around 13 to 16 degrees Celsius is ideal — and not in the refrigerator. Cold is the common mistake: below roughly 10 degrees Celsius sweet potatoes suffer chilling injury that leaves a hard core which never softens in cooking and brings out off-flavours and internal decay, so the fridge does more harm than good. Kept cool and dry they hold for several weeks, while warm room temperature makes them sprout and shrivel faster; do not wash them until you are ready to cook, as surface moisture speeds rot. This chilling sensitivity carries one local caution — a sweet potato left in a freezing vehicle through an Edmonton winter can develop the same hard core and breakdown, so carry them indoors promptly in cold weather.

A sweet potato is past its prime when the skin wrinkles and the root feels light, spongy, or rubbery, all signs that it has dried out. Sprouts at the ends are not in themselves a hazard — a still-firm root can be used after the shoots are snapped off — but they signal age and fading quality. Discard any root with soft wet spots, oozing, sunken or blackened patches, mould, or a sour or musty smell, as these point to rot that can run through the flesh; a single small firm blemish can be trimmed away, but widespread softness or a bad odour means the whole root should go.

Sources:

• UC Davis Postharvest Technology Center — Sweetpotato: recommendations for maintaining postharvest quality. https://postharvest.ucdavis.edu/produce-facts-sheets/sweetpotato
• North Carolina Sweet Potato Commission — Storing and handling sweet potatoes. https://ncsweetpotatoes.com/sweet-potatoes-101/
• Clemson Cooperative Extension, Home & Garden Information Center — Sweet Potato. https://hgic.clemson.edu/factsheet/sweet-potato/