Ware Potatoes

The potato trade separates three destinations, and they are not interchangeable lots. Ware potatoes are graded for appearance and eating quality and move into fresh retail and food service. Processing potatoes are contracted against attributes that matter to the fryer or crisp line rather than to the shopper. Seed potatoes are a distinct trade category altogether: they are planting material, produced under statutory certification schemes with field inspection and health testing, and they are traded on phytosanitary status and generation rather than on how they look on a shelf.

Ware potatoes

Tubers graded and sold for table consumption; judged on size, shape, skin finish, and freedom from defects.

Seed potatoes

Certified planting material traded under a separate regulatory and phytosanitary regime; a distinct commodity category, not a grade of ware.

Processing potatoes

Tubers contracted to a manufacturer against processing attributes such as dry matter, reducing-sugar level, and tuber dimensions.

Ware grading is largely visual and dimensional. Lots are sized against riddle or screen dimensions set by the contract, and buyers specify shape regularity, skin finish, and flesh colour. Because the tuber is sold whole and unpeeled, surface condition carries a great deal of the commercial value: common scab, mechanical wounds, and skin abrasion from harvesting and handling all downgrade a lot even where the flesh beneath is sound.

Greening is the defect that most clearly distinguishes potatoes from other traded produce. Tubers exposed to light — in the field, on the grader, or in a lit display — develop chlorophyll, and that greening accompanies the accumulation of naturally occurring glycoalkaloids in the tuber. Green tubers are therefore rejected on sight, and the whole handling chain from lifting to retail is built around keeping the crop dark. Internal disorders such as hollow heart and blackspot bruising are invisible externally and are assessed by cutting sample tubers.

• Greening from light exposure at any point in the chain
• Mechanical damage, skinning, and blackspot bruising from handling
• Sprouting once dormancy breaks in store
• Common scab and other surface blemishes
• Soft rots and dry rots developing from wounds
• Hollow heart, secondary growth, and other internal disorders

A lifted tuber is a living organ with a dormancy period, and ware storage is the management of that biology. Freshly lifted potatoes are first cured — held warm and humid so that wounds suberise and the skin sets — before the store is pulled down to its holding temperature. Thereafter the store manages respiration heat, water loss, sprout development, and disease, using ventilation and humidity control rather than the drying that governs grain.

Temperature choice involves a genuine trade-off. Colder storage suppresses sprouting and rots but drives cold-induced sweetening, in which tuber starch is converted to reducing sugars; that matters most to fry and crisp colour, and is one reason processing lots and ware lots are held on different regimes. Transport is short-chain and protective: potatoes move in pallet boxes, bulk trailers, and bags, and must be kept dark, ventilated, and away from both frost and condensation.

The ware market is by definition a food market: the tuber is sold to be cooked whole or prepared as bought. Beyond that, potatoes that fall outside table specification have established outlets rather than being discarded — undersize, misshapen, and blemished tubers commonly move to livestock feed or into starch extraction, which values dry matter and cares nothing for skin finish.

Starch manufacture is the principal industrial pathway from the potato. Where starch is a planned output, dedicated high-dry-matter starch varieties are grown for it as a commercial category of their own; out-of-specification ware tubers supplement that supply. This entry models the starch pathway from the traded potato commodity, which is where the ware trade connects to it.