Digging potatoes by hand can feel like an archeological endeavor. Each glimpse of a potato skin peering from the dirt foretells a shape unknowable as an ancient artifact. Out of their invisible incubator the gardener lifts them, great edible totems, glowing dimly. Goddess figures. Animal talismans. Lewd statuary. What great soil culture imagined these? What elaborate underground mythology do they speak for? Without ceremony, we sort the worst specimens into the compost pile and stow the rest in cool, dark corners for autumn suppers.
The potato is a close relative of the tomato, both members of the nightshade family, which contains other, more sinister characters, such as the nightshade belladonna. Native to the European continent, belladonna is extremely toxic to humans and was historically used as both a poison and a medicine. With hallucinogenic properties to boot, belladonna is purported to have be a component of flying ointment, a botanical salve witches applied to their skin to help initiate flight (or perhaps the illusion thereof).
Potatoes play a huge role in modern agriculture and the contemporary American diet, one that disguises their humble origin as a high-elevation plant with limited range and serious toxicity. Native to twelve thousand feet above sea level in the Andean mountains of present-day Chile and Peru, aboriginal potatoes were bitter, fibrous tubers carrying a host of unsettling alkaloids that required careful exploration. Mountain people that collected the tubers may have taken cues from foraging animals that licked the clay soil before eating them. The tight chemical structure of clay adsorbs the plants’ toxins as they pass through the digestive system, protecting the eater from illness.
Over a period of 8,000 years, these potato cultures drew dazzling genetic diversity from this once-foraged food, selecting for flavor, vigor at different altitudes (and temperatures) and disease-resistance. Like pasta shapes in Italy, Andean villages still maintain their own traditional potato varieties. A list of known varieties compiled by Peru’s International Potato Center totals nearly 5,000. It may go without saying that Andean cultivars still hold the majority of the world’s genetic diversity of potatoes.
Of the European explorers who charged through South America, Spaniards were the first to encounter potatoes, and who eventually sent them back to the homeland as a crop with great potential to help feed Europe’s growing population. Knowing only poisonous nightshades, Europeans accepted them with trepidation, and it took centuries for the potato to gain a foothold in European cuisines. When it did, however the potato was unmatched in its ability to provide an economical food source.
As potatoes are cultivated from cuttings of last year’s tubers, potato plantings are essentially clonal monocultures. Spaniards propagated their potato campaign from a small sampling of Andean tubers, thus most of the potatoes in Europe shared nearly identical genetics. Thus when the first European potato field was struck with blight, the rest soon followed, unleashing one of the continent’s longest and most severe famines. Even in contemporary agricultural systems, potato farmers must constantly battle potato blight and their most damaging pest, the potato beetle, with an ever-changing host of chemical arsenals, making conventional potatoes one of the most pesticide-laden foods.
Contemporary dietary lore would have us believe that the potato is a nearly useless vegetable, more at home alongside pies, gravy and other guilt-ridden foods than as a component of a nutritious meal. Potatoes do contain a lot of starch, which is converted by our digestive system into sugar that can wreak havoc if consumed regularly. But all potatoes are not created equally. New potatoes contain up to half the starch of mature potatoes, and have a skin that is thinner and more palatable, meaning we are more likely to consume it. Potatoes eaten with their skins are good sources of vitamin C, potassium, and vitamin B6. Pigmented varieties, especially blue potatoes, also contain phytonutrients that are being explored as possible cancer inhibitors and hypertension regulators.
Even the starch component of potatoes, once a reliever of famine, now a contributor to obesity, can be tamed to our advantage. Potato starch comes in two forms, one that is easily converted to sugar in the time it takes to pass through our digestive system, and one that resists the digestive process, providing some of the same benefits as fiber. Freshly cooked potatoes contain the highest levels of digestible starch; cooling potatoes after cooking converts some of the digestible starch into resistant starch. Reheating cooled potatoes does not convert the resistant starch back to its digestible form, so the simple trick of pre-cooking a baked potato for reheating the next day dramatically reduces its glycemic index.
As the holidays approach and potatoes inevitably make the shopping list, consider focusing your culinary whims on their more positive attributes: an array of colors signaling powerful phytonutrients, nourishing skins that add texture and flavor to even the most classic potato preparations, and convertible starch, whose technique demands potatoes be half-prepared well in advance—a requirement we can happily succumb to during the busy holiday season.