Potatoes (Solanum tuberosum) are a hugely important member of the powerful Nightshade clan, in both economic and culinary terms. Introduction to Europe and Asia from their home in Peru, potato eventually became a dependable staple in many countries that had relied on failure prone grain crops. The bonus is that potatoes taste really good and can be cooked in innumerable ways. Photo by U.S. Department of Agriculture = public domain.
Potatoes originated in southern Peru and were already an important cultivated crop in Peru and Chile 10,000 years ago. They are well adapted to growing at high altitudes and under harsh conditions. Photo © i0013.
Brought to Spain from Peru in 1565, potatoes were first grown as a curiosity in botanical gardens. They were so obviously relatives of the toxic black nightshade most people didn't taken them seriously as a food crop. Spanish and French sailors, however, found eating potatoes warded off scurvy, a much more serious threat than a little poisoning.
Sir Walter Raleigh brought potatoes to his Irish estate around 1589. It is said they came from Virginia but that is probably wrong, they probably came from a captured Spanish ship. The story is, he later sent some to Queen Elizabeth. A royal banquet featuring potatoes was ordered, but the cooks were not instructed. They tossed the root tubers and cooked the greens. There was great sickness in court that day and potatoes were banned by order of the Queen. I have not been able to verify this story, but even if it isn't true it ought to be.
Another story is that potatoes were introduced to Ireland from ships of the Spanish Armada, wrecked by storm on the emerald shore. Both stories could be true.
Germans were the first to take potatoes seriously as food, in hopes of supplementing failure prone wheat crops. They tried very hard to make bread out of them and that didn't work ("potato bread" is almost all wheat). Having failed, but with substantial plantings, the Germans tried feeding potatoes to their pigs. The Germans, figuring that many pigs could not be wrong, learned to boil, fry and bake potatoes as vegetables.
A Frenchman named Parmentier learned about potatoes in Prussian POW camps during the 7 years war. He introduced them to France by agreement with king Louis XVI. The French found their dogs wouldn't eat them so would have nothing to do with them. Parmentier planted 100 acres of the king's land with potatoes and the king's soldiers kept them under 24 hour armed guard. One day the soldiers were given the night off and potatoes were soon growing all over France.
In Ireland potatoes became particularly important after the English conquest of the early to mid 1600s. The English took all the good land, all the money, cut the forests to build ships and shipped most food crops directly to England. The Irish, left landless and unemployed, had nothing to do except eat potatoes and procreate. This resulted in a huge population increase. Then came the potato blight of 1845 to 1849. The population was reduced by about half (from around 9 million to a bit over 4 million) through starvation, disease and emigration.
Though brought over by Irish immigrants, potatoes were still viewed with suspicion in North America until about 1900 when a potato variety developed by Luther Burbank became widely grown in Idaho. It was soon accepted in most of North America.
Potato developers continue to experiment with new varieties and cross breeding with ancient varieties from Peru and Chile (our commercial potatoes are mostly of Chilean ancestry). We now have potatoes of many kinds, sizes and colors with different flavors and cooking properties to chose from.
Washington State University (P1) lists 575 varieties of potato grown in North America. Thousands more are grown in Peru alone and more than 5000 worldwide. Those listed here are typical of the types sold in North America. The exact variety can be critically important to food processors and fast food chains, but home cooks can just go with the general type and be fine.
A note on names - not only do many older varieties go under different names in different regions, newer varieties often have names trademarked by the developers. Other developers may produce almost identical potatoes but must call them by a different (often similar) name.
Of course, the cultivars I have listed here are all North American since that's what's available in my local markets. For British varieties see the excellent Potato Council Web site. Australians have some of each and then some.
Baking Potatoes: -
[Russets, Idaho, Russet Burbank, Norgold Russet & many more]
These potatoes have thick, rough (russeted) medium brown skins, low sugar and a high starch content with amylose starch predominating. They have a dry, mealy flesh and are preferred for baking and mashing. The photo specimens were 5.4 inches long and 2.7 inches wide, weighing 10-5/8 ounces.
These should never be wrapped in foil for baking. They should not be used in soups and stews unless they are primarily a thickener because they will disintegrate. They are very good for frying - some cooks feel they are the only potato worth frying. Baking potatoes have good storage properties and can easily keep for weeks in a cool dark place with good air circulation.
The common Russet Burbank was developed by Luther Burbank as a blight
resistant potato for Ireland, since the Irish would apparently rather starve
than eat any other kind - and russets are the only kind used there to this
Boiling Potatoes: - [Maine
Potatoes, Eastern Potatoes, Round White, Red Bliss, Red la Soda, Superior,
They are almost never baked and don't work well for mashing either,
producing a heavy, lumpy mash. They are best where you want potatoes,
slices or cubes to remain intact through wet cooking, particularly in soups
and stews. Round white potatoes predominate in the Northeast US while only
red varieties are found in the Northwest and California.
All Purpose Potatoes: -
[California Long White / White Rose, Kennebec, Yukon Gold]
They are a bit expensive because the cost of growing and harvesting is much
higher than for larger potatoes. They are used mainly in salads and
other recipes where they will be particularly obvious and are called for by
some Indian and other ethnic recipes.
Photo © i0012.
New Potatoes: - [Early Potatoes]
Due to extra care in harvesting new potatoes are expensive, but are much in demand. They are usually used whole in very simple recipes where their flavor will not be concealed, usually cooked by roasting or steaming. They are quite perishable and should be used within a few days
The term "new potato" has been somewhat degraded, mainly because so many recipes call for them even though they're not readily available. Many people don't know that "new potato" means anything except "small", but small mature potatoes are properly Creamers, not "new".
Some refer to red potatoes generically as "new potatoes" but this is in
error. Reds are the potatoes most often harvested as "new" but they are not
generically "new", they must be very young just like any other new potato.
Photo © i0009.
- [Tunta (Bolivia)]
These are freeze dried potatoes that have been produced by the Inca and
Tiwanaku cultures for over 1000 years (that we know of). Frost resistant
potato varieties are frozen by night and thawed by day and trampled under
foot for three days, then let freeze and thaw an additional two days to
produce the dehydrated product. White chuño is washed between
freezings and black chuño is not. These can be stored for over
a year and are important to traditional cuisines in Bolivia and Peru.
Photo © i0008.
The potato's reputation for being fattening is not so much from the potatoes themselves (not much more so than apples), but the oils, butters and sour cream they are often cooked in or eaten with. Potatoes contain no fat or cholesterol.
Potatoes are about 75% water and 19% complex carbohydrates, and are sufficiently nutritious a person could maintain good health on a diet of just potatoes and milk (for vitamins A and D). A fair amount of the vitamin and mineral content is near the surface, but more than half is distributed throughout the interior.
Vitamins and Minerals: Potatoes are high in vitamin C, to the extent Spanish and French sailors consumed potatoes to ward off scurvy just as British sailors consumed lime juice and the Germans sauerkraut. They are also fairly rich in vitamin B6 and contain significant amounts of Thiamine, Niacin, Iron, Magnesium, Phosphorus and Potassium. Potatoes contain more potassium than any other common vegetable, or even bananas. Potassium mitigates the effects of sodium in salt.
Protein: Potatoes are about 2% protein and that protein is a very balanced mix of amino acids. The protein is almost all right under the skin so to take advantage of this nutrient potatoes should be cooked skin-on and eaten whole or with just the papery skin removed after cooking.
Dietary Fiber: Fiber is provided mainly by the skin, but the flesh contains an indigestible starch which provides the same benefits. This form of starch in a cooked potato is about 7% but if the potato is allowed to cool it will increase to about 13%.
Toxicity: Despite assurances by the Michio Kushi Macrobiotics folks that potatoes will send you to an early grave, demographics do not support this claim. The foliage and fruit of the potato plant do contain significant levels of the powerful neurotoxin solanine, and this toxin is not destroyed by normal cooking. The root tubers of domestic potatoes contain very little solanine and new varieties are tested for this. In any case, most of the solanine is within 1.5 mm (1/16 inch) so peeling even quite thinly will remove most of it.
The amount of toxin in a potato may increase if it is exposed to light and turns green, but this is not a reliable indicator. Bitterness is a better indicator as Solanine is an alkaloid. Greening can occur without significant increase in toxicity and toxicity can be present without greening. Diseased potatoes or those showing decay may have elevated levels of solanine and should be discarded. Individual tolerance is said to vary, but I've eaten plenty of lightly greenish potatoes without ill effect, and no cases of potato poisoning have been reported in the United States for about 50 years.
There are rumors red potatoes are unaffected by greening and increased toxins, but this is unlikely, it's just a lot harder to detect in red and purple potatoes. Measurement of solanine is not at all easy, so it's unlikely reliable data is available.
Strangely, some sources (FDA and Wikipedia) say solanine toxins are water soluble, but most analysis sources say it is not. On the other hand, it is apparently soluble in water to which citric acid has been added - but I don't have anything reliable on effective level of acidity.
Acrylamide: This substance was detected in fried potato products in Sweden in 2002. It is not unique to potatoes but occurs in all high carbohydrate foods when heated, like toast, for instance. It has been in our food since the invention of cooking.
Acrylamide has been shown to cause cancer in some laboratory animals when they are fed massive doses of it over a period of time. Whether there is any danger to humans in the dosages we're likely to consume is totally unknown, to the extent health authorities are unable to provide meaningful warnings or set limits.
If you are concerned about acrylamide and want to minimize your exposure without seriously compromising the range of flavors in your food, you should brown your carbohydrate containing foods to a light golden color rather than darker. Toast should be toasted to the minimum color acceptable and the same for rice, corn and potato products.