The Man Who Ate Everything (7 page)

For some time now, I have been unhappy with my mashed potatoes. This is a pivotal difference between me and Omar Sharif, who is so pleased with his mashed potatoes that, according to the glossy magazine on my desk, he always has a second helping. His mashed potatoes really belong to Joel Robuchon, the brilliant chef-owner of the Paris restaurant Jamin, and for several years they have been the most honored mashed potatoes in the world. They are also an escapade in animal fat. Judging from the recipe in Robuchon’s
Ma cuisine pour vous
(Laffont, 1986), he beats a half pound of butter into each pound of boiled potatoes. In the ten minutes it takes Omar Sharif to clean his plate, he will have swallowed ten times the maximum daily dose of animal fat allowed by the U.S. surgeon general, before he gets to his main course. This is precisely why mashed potatoes and the other fashionable comfort foods have become so important to us. They let us feel chic and trendy without having to eat tuna carpaccio and fava beans. Considering the smear campaign against dietary fats being waged by the surgeon general and his ilk, mashed potatoes are a godsend.

But while Omar Sharif swans about Paris, my mashed potatoes still get gummy on me. Sometimes they go cataclysmically wrong, turning sticky and gluey or doughy and pasty, bonding to my teeth and gums and the roof of my mouth, coating my tongue and throat.

As luck would have it, the instant mashed potato industry is even more panicky about sticky potatoes than I am. An average potato, on its long journey from loamy meadow to those packets of dehydrated granules on your supermarket shelves, undergoes such intricate torture that its aptitude for gumminess is amplified many times over. Industry scientists, whose careers depend on preventing potatoes from turning out that way, publish their findings in various technical journals here and abroad, which a teacher in Atlanta named Shirley Corriher, who is writing a book on the science of cooking, showed me how to find with my personal computer. Of the 341 papers written on mashed potatoes in the past twenty years, thirty seemed especially worth reading, as did
Potato Processing,
the bible of the industry. The USDA did much of the early work on instant mashed potatoes, and its expert in California, Merle Weaver, was particularly helpful to me over the telephone.

What follows is a series of small suggestions for making good mashed potatoes and one big suggestion. Whether to label the latter a major breakthrough in home culinary science is for others to judge.

Let’s get acquainted with the potato.
The potato is the most important vegetable in the world. Ten billion bushels are grown every year, almost half of them in Russia and Poland, where vodka is extremely popular. Mashed potatoes whipped with milk are a nearly perfect food that single-handedly nourished nineteenth-century Ireland until the potato blight struck and things turned rough. Without milk, potatoes will keep you alive for 167 days if you can stomach 3
3
/4 pounds of them a day. The average American consumes one medium potato a day, or 110 pounds a year, as often as not in processed form—chips and other snacks, frozen French fries, and instant granules—and derives more vitamin C from potatoes than from citrus fruits. (Back in the days when citrus was still a tropical rarity, potatoes offered the main protection against scurvy.) Raw potatoes are 70 to 80 percent water (making them almost as wet as milk) and 10
to 20 percent starch, with the remainder in sugars, fiber, minerals, and high-quality protein. A potato contains virtually no fat and about as many calories as an apple or a banana.

The potato plant is a perennial herb of the Solanaceae family with purple or yellow flowers and, occasionally, a fruit that looks like an amiable little green tomato but poisons you like the berry of the nightshade. The edible potato is not a root vegetable at all but a tuber—the swollen tip of the plant’s underground stem. The eyes of a potato are not arranged randomly but continue the pattern set on the stem by its branches and leaves: a spiral with thirteen leaves or eyes for every five turns of the helix. Sugar is manufactured in the leaves and transported to the underground tuber, where it is turned into starch.

Why your potato turns gummy.
Like other living things, a potato is composed of millions of cells all cemented together. Lining the walls of each potato cell are hard, closely packed microscopic granules of starch, impervious to the water that fills the rest of the cell. But when you heat a potato to about 140 degrees Fahrenheit, the starch granules begin to absorb the water around them, and by 160 degrees they have swollen to many times their original size. The starch is now a gel, a viscous complex with water, and fills up most of the cell. Separate, swollen, and perfectly intact potato cells make for smooth mashed potatoes. But at 160 degrees the cells are still strongly bound to one another, and if you try to mash the potato now, the cells will split rather than separate, and the starch gel will ooze out of them.

This is called free or extracellular starch, and
it is the enemy.
Free starch turns mashed potatoes gummy.

As the cooking time lengthens and the internal temperature of the potato increases to 180 degrees, the cement between the potato cells—pectic material similar to the pectin that thickens jams and .preserves—begins to degrade, and the cells can now separate from one another. This is a good time to mash your potatoes. With further cooking, the cells begin to weaken and rupture, and some of the gelled starch leaks out. That’s why overcooked potatoes become sticky and gluey even though they are easy to mash. If 15 or 20 percent of the cells in your potato are ruptured, you will be very sorry.

Buying your potato.
One common way of categorizing potatoes is by their starch content. A mealy or floury potato like the Russet Burbank is dense, high in starch, low in water, and, despite the distasteful sound of the word “mealy,” generally preferred in this country for mashing. A waxy potato like the White Rose is low in starch, high in water, and often specified in French recipes. (Joel Robuchon’s potato is the BF 15; translated from the French this means a small yellow-skinned potato with dark yellow waxy flesh.) The adjectives “mealy” and “waxy” refer to the texture of the potato after you cook it. Mealy potatoes become fluffy and almost grainy when you mash them; waxy potatoes become creamy and smooth. But waxy potatoes generally require longer cooking and greater mashing force to separate the cells. Some researchers feel that more free starch is thus released, increasing the risk of gumminess.

Once you have decided which type of potato to cook, just try to ask your greengrocer or the guy stamping prices on laundry soap at your supermarket to point out the waxy potatoes and the mealy ones. Your reward will be an uncomprehending stare. But you can test the potatoes yourself. Buy one of each and, when you get home, mix a bowl of brine with nine and a half cups of water and one cup of salt. If a potato sinks into the brine, it is high in starch and will cook up mealy. If it floats, it belongs in the waxy category—unless it suffers from a potato ailment called hollow heart, in which case it will probably float in anything. All the potatoes at my grocery sank.

I used only large mealy Idaho russets in my mashed potato experiments. Avoid recipes that fail to specify which type of potato to use. Also avoid recipes that call for something like “six medium potatoes” without giving their total weight. Potatoes
vary in size even more than human beings. If the cookbook specifies neither potato type nor total weight, discard it immediately.

Peeling and cutting your potato.
The potato-peel lobby would have you believe that all the nutrients are in the skin. Nothing could be farther from the truth. The peel does contain a
disproportionate
share of vitamins and minerals compared to its negligible weight, but most of the nutrients are nonetheless found in the flesh of the potato and not in the peel. Cooking a whole potato in its peel does prevent some vitamins and flavor from leaching out into the salted water, but cooking any potato whole, whether you peel it or not, leads to uneven cooking when the rounded ends and outside layers become overcooked before the inside is ready. Overcooked cells will rupture.

If you peel your potatoes and cut them into pieces of the same size, they will cook evenly and quickly. Tiny pieces cook fastest but lose more nutrients and flavor because their total exposed surface area is larger. The best compromise is to cut peeled potatoes into slices between five-eighths and three-quarters of an inch thick. Wash them under cold water to rinse off any free starch released when you cut open the cells in peeling and slicing.

Cooking your potato.
This is where we part company from all domestic mashed potatoes that have gone before us.

Years ago the instant mashed potato industry found that if you precook potatoes in 163-degree water for twenty minutes (twice as long for waxy varieties) and cool them, the amount of free starch in the final mash will be reduced by half. Without this discovery the instant mashed potato industry would today be manufacturing laundry starch.

I have experimented with both techniques and am guardedly optimistic that precooking may be the answer to our prayers. It appears to work like this. Cooking a potato is a two-stage process. The starch swells and gelatinizes within the cells when the potato reaches 160 degrees; then, nearer to the boiling point, the pectic
c
ement between the cells degrades, and the potato can be safely mashed. Precooking separates these steps. Cooling the potato slices after the starch has gelled causes a process called retrogradation to take place; the starch molecules bond to one another and lose much of their ability to dissolve again in water or milk, even if you later rupture the cells through ricing or mashing and even if you overdo the final cooling a bit. Retrogradation retards gumminess.

For the first time anywhere industrial precooking and retrogradation can now be brought into the home kitchen. The use of a thermometer is vital. Put the peeled and washed slices into a pan of 175-degree water. Keeping the pan on a low flame and adding a little cold water now and then, you will find it easy to maintain the water within a few degrees of 160 for the next twenty or thirty minutes as you go about your other tasks. The slices will become tough and resilient and lose their translucent appearance. Drain the potatoes and transfer them to a bowl into which you run cold tap water until the slices feel cool to the touch, and leave them there for the next half hour. Then proceed to the final cooking, either simmering or steaming. Some recipes have you put your potatoes into cold salted water before bringing them to the boil. An elaborate Swedish study has shown that potatoes cooked this way produce a stickier final mash and sometimes develop an odd flavor. Other studies demonstrate that more vitamin C is lost if you start with cold water. Better drop your potato slices into actively boiling salted water and lower the heat to just above a simmer.

Last night I tested four versions of mashed potato on my guests. The precooked version came in first. It was smooth, not gummy, and had a robust earthy potato taste. The runner-up had been boiled in salted water in the usual manner. It verged on the pasty but tasted good. The other candidates were hopeless.

Mashing your potato.
Mash immediately after you drain the potato slices. The goal here is to separate the cells without rupturing them, and the perfect temperature for achieving this is
about 180 degrees Fahrenheit. As the potato cools to room temperature, the pectic cement hardens again, and many more cells break open when you mash them, spilling out their sticky starchy gel. At 50 degrees half the cells will rupture.

Any cookbook that sanctions the use of a blender or food processor for mashing should be carefully shredded. People who like to use a hand masher because the resulting lumps remind them of their mothers’ cooking ignore the fact that this technique repeatedly abuses the already mashed portions of the potato while you seek out the solid pieces that remain. A ricer is best because each potato cell passes through it only once, and all the pressure is applied in a vertical direction. In contrast, a food mill shears more cells apart by scraping them across the screen as you turn the handle, but it is possible that our precooking technique will permit the use of a food mill without fear of gumminess and produce a perfectly smooth result at the same time. Further experimentation lies ahead.

Steamy cooked potatoes should be dried either before or after mashing. You can return the slices to the pan, cover them with a folded kitchen towel, and shake the pan every so often for the next five minutes. Or you can rice the potatoes back into their pan and stir over low heat for a minute or two until a film appears on the bottom of the pan. Use a softly rounded wooden spoon. Be gentle.

Enriching your potato.
How much butter you add is your business. I find that a stick of butter for every two pounds of potatoes (serves four to six) is a bit austere but that Robuchon overdoes it with three or four. If you beat in the butter first and then
hot
milk or cream (over low heat), you can achieve any consistency you like, from runny to stiff, but if you do it the other way round, it is hard to know how much milk to add. Georges Blanc advises incorporating the butter right away, keeping the potatoes warm, and adding heavy cream at the last minute. If you hold mashed potatoes for a while over warm, not simmering, water,
don’t cover the pan completely or the flavor will turn on you and gumminess set in.