Answering the Root Questions
Now, I could tell you all about the arcane facts that potatoes are tuberous herbaceous perennials and that they are a member of the genus solanum, or “nightshade,” hence the early belief they were poisonous. I could go on to mention that they are native to southern Peru, where they were domesticated somewhere between 7,000 and 10,000 years ago. And how the Spanish introduced them to Europe in the late 16th century. And how they became an essential part of the Western diet, especially in places like Ireland where a fungus-like blight destroyed much of the crop in 1845 leading to the Great Famine. But what you really want to know is what the difference is in all the varieties you see in the supermarket and which spud is best for mashed potatoes or French fries or beef stew, right? So I'll tell you.
There are nearly 4,000 varieties of potato. Of course, you only find a fraction of that number in the produce department, but the difference can still be confusing. So, why so many potatoes?
Generally speaking, for culinary purposes there are two basic types of potato; starchy and waxy. There's a kind of subcategory that's somewhere in the middle, but we'll get there in a minute. Starchy potatoes have more starch (20% - 22%) than waxy varieties (16% - 18%.) As a result, they are usually drier and flakier than their less starchy cousins. This makes them a better choice for baking, mashing, and for use as French fries. They're also okay for boiling, but they don't hold their shape very well in long-cooking applications, so they're not a good choice for soups, stews, casseroles, and such. Waxy potatoes, often sold as “boiling” potatoes, are more dense and tend to hold their shape better, making them a more appropriate choice for boiling and roasting and for use in soups and stews. That somewhat nebulous middle category is populated by a few varieties that are both starchy and waxy, allowing them to serve as more or less all-purpose potatoes.
Beware of green potatoes. You'll often find potatoes in the grocery store that have been exposed to light. Potatoes really need to be stored in the dark, but obviously supermarkets can't very well build little dark rooms for them and give you flashlights to go in and make your selection. So they just kind of lay them out there on big tables under bright fluorescent lights and the poor little buggers essentially get sunburned. Same thing happens if you don't properly store them at home. So what's the big deal about a little greenishness? Solanine. Solanine is a glycoalkaloid poison found in members of the nightshade family. Potatoes produce it naturally as a defense against critters. See, as delicious as we think they are, they don't really want to be eaten, so they figure to take you down with them. The green coloring itself is just harmless chlorophyll, but its presence is an indicator of an increased toxicity that can cause nasty gastrointestinal issues. In sufficient quantities, solanine can even be fatal. To that extent, the old time Europeans who thought potatoes would kill you were right. But fear not, spud lovers. You'd have to consume an awful lot of green skin to get sick. And all you have to do to be on the safe side is peel away the green parts. What's under them is fine.
The same thing is true of “eyes,” the little whitish-greenish sprouts you sometimes find sticking out of your potatoes after they've been in the pantry awhile. When potatoes begin to sprout “eyes,” it means the starches in them are being converted to sugars, a sign that the nutrients are beginning to leech out and the quality to deteriorate. Besides being mildly toxic, “eyes” are bitter as all get out, so just get them out. The only time you really need to toss a potato is if the skin has gotten loose and wrinkly or if the potato itself is really soft and squishy. Such tubers have gone 'round the bend and should not be eaten.
Also on the subject of storing and starch conversion, if you're one of those folks who like to store potatoes in the refrigerator.......STOP THAT! Cold accelerates the process of converting starch to sugar and you might be unpleasantly surprised to find that your refrigerated spuds turn black on the inside when you cook them.
Oh, and by the way, if you have ever awakened in the middle of the night with the question, “Why are potatoes called 'spuds'” burning in your brain, I can help. A “spud” is an old-timey digging implement. With a sharp-edged narrow blade, it is the ideal instrument for digging up plants, especially those with large roots. Like potatoes. The first documented application of the tool name to the object it dug up occurred in E.J. Wakefield's “Adventure in New Zealand” back in 1845, with the nickname gaining common English usage soon thereafter.
Okay, enough trivia. Let's get to the root question (sorry, had to do that); what kind of potatoes should you buy?
|Burbank Russet Potato|
|Yukon Gold Potatoes|
Canada's “gold rush” country. The “gold” is a reference to the potato's rich yellow color, caused by a flavenoid compound called “anthoxanthin.” There are other yellow-fleshed potatoes on the market, most notably Yellow Finn, Michigold, and Delta Gold, but the Yukons currently have a lock on popularity. These yellow-fleshed potatoes are a medium starch variety, which means they fit into that “in between” area I mentioned earlier. Dense and creamy, they have a mild buttery flavor which makes them well-suited for mashing and baking, but they are also good for frying, roasting and boiling. That's why many people consider them the ultimate “all-purpose” potato.
skins are markedly lighter in color and are also thinner than Russet skins. The Kennenbec is an example of a long white potato. Round whites look kind of like common red potatoes in size and shape, but, obviously, they have light skins. The difference is in the starch content. They have more starch than reds, making them a versatile potato for most cooking applications. They are particularly good in scalloped or gratin dishes, and do well when roasted or used in potato salad. Usually just called “white potatoes,” they can sometimes be marketed as Atlantic, Norwis, or Superior.
Okay, we've discussed reds and whites, now let's talk about blues. When I was a kid learning to cook back in the '60s, if I would have cut open a potato that was purple or dark blue inside, I would have said “yuck!” and thrown it away. But purple and blue potatoes have come into their own in recent
years. Native to South America, they are still fairly
uncommon in most US markets, but they are gaining in popularity as
more and more chefs highlight their unusual subtle nutty flavor. Most
blue/purples are medium starch. They vary in size and shape from
large marble through fingerling up to a medium round. They can be
baked, steamed, or boiled and actually do quite well in the
microwave, which preserves their unique dark blue to lavender color.
And they look really cool on a plate. Available varieties include All
Blue, Purple Majesty, and Purple Peruvian.
of colors, but most are yellowish. They are a more waxy potato, which makes them perfect for roasting and boiling. They can be pan fried or used in any application where a medium to waxy potato is appropriate. But they are small and still kind of on the expensive side, so most cooks highlight their unusual shape by roasting them and serving them whole or halved.
So, now you know everything you need to know about potatoes. Well......almost. At least now you won't have to wander around the produce section looking confused. And, armed with the knowledge of what potato does what, you're ready to tackle some new recipes or improve upon some old ones. Mashed potatoes, baked potatoes, creamed potatoes, French fried or home-fried potatoes, hash browns, potatoes au gratin, scalloped potatoes, herb roasted potatoes, gnocchi, fondant potatoes, Dauphinoise potatoes, Hasselback potatoes, Duchess potatoes, tater tots, homemade potato chips..........I gotta go. I'm getting hungry.