I ask you to reconsider the humble acorn. This nut from the oak tree falls to the ground by the thousands, in nearly every state in the nation and in scores of shapes and sizes. You probably walked past several today. Acorns are all around us, yet rare are the people who can say they’ve ever eaten them. Eating acorns is uncommon even among dedicated foragers.
Oh, I know what you’re thinking: They’re poisonous. Intolerably bitter. Flavorless. Too much work to shell. Too much work to process. Not worth the effort. Mealy.
None of this is true. Making acorns good to eat is far easier than many other cooking tasks we do cheerfully on a weekend and can take far less time than you might think.
I first learned that acorns could be eaten as a high school student, when my class went on a field trip to see a 300-year-old white oak tree, planted when the town was newly founded. It was the biggest tree I had ever seen, and I was astounded at the sea of fallen acorns around it. I pointed at them and asked the teacher, “Can you eat those?”
“Some people do,” she said. Who? “Indians, I think.”
This was New Jersey in the 1980s. I’d never even met an Indian, let alone met one who ate acorns, and I soon lost interest in eating acorns. Some years later, while reading Euell Gibbons, I learned again that yes, acorns can be eaten. But even the great Euell largely wrote off acorns as too much work. Still, every so often I’d eye a giant oak standing amid a swath of acorns and wonder.
Finally, a few years ago, Holly and I sat down at Incanto, a fancy restaurant in San Francisco. Looking over the menu, I stopped short: “Acorn Soup.” I asked the waitress if this was acorn squash soup. “No, it is made with acorns. The chef made it himself.” I ordered the soup, and it was good—pureed, thick, like a woodland version of potato-leek soup. Monochromatic, yes, but tasty. I asked the chef, Chris Cosentino, how he did it. Cosentino said it took several days of leaching to remove the bitterness from the acorns.
Several days?! I went back to Gibbons’s book and reread the chapter on acorns. According to Gibbons, it took hours, not days. He just boiled the acorns in several changes of water. I became determined to repeat Cosentino’s soup, using Gibbons’s method.
A year went by. I was busily collecting green olives with my friend Elise when I stumbled on a huge fall of California valley oak acorns. Within minutes, we’d gathered about 10 pounds. Game on! A few weeks later, I processed the acorns one morning while watching college football. Without missing a play, I had them ready to eat by the end of the game. Anyone who has ever made his own stock or homemade pasta, filleted a fish, braised beef short ribs, baked and decorated a layer cake, or planted a garden can process acorns.
Turns out we can learn something about processing acorns by watching squirrels, who love them very much. Squirrels don’t bury every acorn they find. Scientists observing squirrel behavior in the East noticed something unusual. The fuzzy varmints would seek out white oak acorns and gorge themselves—then dash off to find and bury the acorns of other oaks, mainly the red oak. Why? Turns out white oak acorns are low in the bitter tannins that give all acorns such a bad name. Red oak acorns tend to be high in tannins. But tannins are water soluble. So by burying the red oak acorns, the squirrel hid them from the stealing blue jays (and rival squirrels) and plunked them into water-rich soil. After rain and snow and freezing and thawing, the tannins leach into the soil and leave the red oak acorn sweet enough to eat.
This brilliant feat performed by what is essentially a bushy-tailed rat is the best way of showing you that there are acorns and then there are acorns. Some really are so bitter or small that they’re not worth eating. But others, like the eastern white oak, the bellota oaks of Europe, and the Emory oak of the Southwest, are sweet enough to need minimal or, in rare cases, no processing.
Unlocking the secret of acorns goes a long way toward solving what I call the Forager’s Dilemma. If you are a skilled hunter-gatherer, finding meat and fish is not terribly difficult. And wild greens, berries, and other yummy plants are pretty easy to find, too. Where things get tricky is that third leg of the nutritional stool: starch. For the most part, finding a sufficient supply of this staff of life is no easy task in the wild. Unless you are near a swamp—where there are several wild sources of carbohydrates, such as the cattail and the arrowhead plant—there is no easier way to collect sufficient starch for a whole year than to collect and process acorns. This is what many Native American groups did, especially in California. Keep in mind that I am not suggesting you give up wheat or potatoes or rice for a diet of acorns. But as a piece of a diverse diet, acorns deserve a place in serious modern cooking.
Chestnuts and acorns share enough culinary traits that any chestnut recipe can become an acorn recipe. In fact, acorns have been used interchangeably with chestnuts in Europe and North Africa for millennia. They are still eaten with some frequency in Korea. While not easy to find, you can suss out a few acorn recipes from the Berbers, Spanish, Italians, and French. Farther north, the Germans drink an acorn coffee.
With few exceptions, however, acorns have been stigmatized as famine food nearly everywhere in the world. North African Berbers still use acorns, however. I corresponded with Paula Wolfert, who wrote the great Couscous and Other Good Food from Morocco—the sine qua non of Moroccan cookbooks—and she said that Berbers will sometimes make couscous from acorn flour. Linda Berzok, who wrote American Indian Food, says that the Native Americans around Tucson, Arizona, sell roasted acorns from the Emory oak, which they say are so sweet they don’t need leaching. An expert on Mexican food told me that in Chihuahua they do the same thing; the Emory oak lives there, too.
My first experiment with acorns was as a coffee substitute. I collected the acorns, then shelled, leached, dried, and ground them into flour. Then I put 2 tablespoons in a press pot and poured boiling water over it. I let the mixture steep for a few minutes and poured it into a coffee cup. It was not black, like the chicory coffee I often make. In fact, it looked like it already had a little cream in it. I put some sugar in the cup and tasted it . . . and I’ll be damned if it didn’t taste uncannily like tea with cream in it. But that’s just one of many ways to make acorns shine in the kitchen.
Using acorns as food pretty much falls into three categories: eating acorns as nuts (they are a lot like chestnuts), making acorn flour, and cooking in acorn oil.
First, you need to get yourself a supply of acorns. Go find some oak trees—they’re the ones with all the acorns that have fallen down around them. But what kind of oak is it? Oaks come in so many varieties you should check the leaves against a guidebook. A general rule is that the leaves of white oaks, the acorns of which tend to be less bitter, have soft edges, while the leaves of the red oaks, the acorns of which tend to be more bitter, have spiny or pointy edges. Western oaks also fall into these categories: For example, valley oaks are in the white oak family, while live oaks belong to the red oak tribe. Tan oaks are their own thing, but their acorns generally taste more like red oaks’.
When can you gather acorns? Start as early as Labor Day, while many are still green but fully formed; then again in fall when they, well, fall; in winter, when there is no snow to cover them; and even in spring, when they are beginning to sprout. Suellen Ocean, who wrote a very useful book called Acorns and Eat ’Em, says she likes to collect tan oak acorns in February and March, after many have begun sprouting. She says acorns with sprouts between 1 and 2 inches long are still good to eat, but discard any acorn meats that have turned green. This is sound advice. Spring gathering has an added bonus: Recently sprouted acorns have begun to turn their starch into sugar and are foolproof. “If it is sprouted, it’s a good acorn and I haven’t wasted time gathering wormy ones,” she says.
A word on worms. When I gathered all those valley oak acorns in October, little did I know that I had gathered scores already infected with the larva of the oak weevil. They’re nasty little maggoty things, and you can tell they are inside your acorn if there is a little hole in the shell. Discard any acorns with holes, and move on. Also toss any fallen acorns that still have their “hats” on. The oak may have jettisoned this acorn because it was infected or otherwise defective. Note that a split shell is not necessarily an indicator of a rotten acorn.
You need to know what kind of oak you are dealing with. Different oaks bear acorns with different shapes, so that can help you determine which sort of oak it is as well as the leaves can. Not all oaks will set acorns every year, so you won’t find acorns from every species every year.
Acorns are a wild food, and as such you must contend with their tremendous variability, both in species and even among individuals of the same species. Some oaks bear acorns so low in bitter tannins that they can be eaten with only one or two changes of water. Legend says that California’s Native Americans fought over these trees. One mature valley oak can drop 2,000 pounds of acorns in a really good year. A ton of sweet acorns may well be worth fighting over.
University of California, Riverside professor David Bainbridge wrote in a 1986 academic paper that, depending on the species, acorns can range in fat content from 1.1 to 31.3 percent, protein from 2.3 percent to 8.6 percent, and carbohydrates from 32.7 to 89.7 percent. That is a wide disparity, which means that in the kitchen, you treat acorns from different species very, very differently. A fatty acorn will make a meal, like ground almonds. A carb-rich acorn—like valley oak acorns—makes a drier flour, more like chestnut or chickpea flour.
For the most part, all acorns can be used interchangeably. The fattier ones taste better when used as something other than flour, and the sweetest ones need the least processing. Here’s a general breakdown.
“SWEETEST” ACORNS (MEANING LOWEST IN TANNIN): East Coast white oak, the Emory oak of the Southwest, the pin oak of the South, the valley and blue oaks of California, the burr oak of the Midwest, and the cork oak and the bellota oak of Europe. California readers should keep their eyes peeled for the many cork oaks and burr oaks planted in towns and cities there.
LARGEST ACORNS: Valley oaks and their acorns are huge, as are white oaks. Burr oak acorns are large, too, as are those of the California black oak.
FATTIEST ACORNS: There is not a lot of detailed data on the eastern species, although I have read that the Algonquin Indians used red oak acorns for oil. In the West, the fattiest acorns are from the live oaks, both the coastal and the interior live oak, as well as the California black oak, Quercus kelloggii. Be certain to refrigerate anything made from these acorns, as the rich oil turns rancid fast.
Shelling acorns is the most onerous part of dealing with them. They have an elastic shell that resists normal nutcrackers. Unless you buy a fancy nutcracker, which you should do if you plan to process large amounts of acorns, whacking them with a hammer is the best way to open up the nuts. Some people use a knife, but that seems dangerous given how slick the surface of an acorn can be.
With a few exceptions, all acorns must be leached with water multiple times to remove bitter tannins. Those tannins not only will make your mouth feel and taste like felt, but also can make you a bit nauseous and possibly constipate you for days.
Getting the tannins out is the big barrier to cooking with acorns. The fastest method is hot-water leaching. After shelling, drop the acorn meats directly into a stockpot two-thirds full of water. Fill the pot about one-third of the way with shelled acorns and boil the water, which will turn dark. As soon as the water boils, pour it into the sink, leaving the acorns in the pot. It’s okay if you still have a little water left over in the pot. Repeat the process. It requires about five changes of water to get valley oak acorns to taste like chestnuts. Don’t even begin to taste test your acorns until four changes of water, and some, such as live oaks, need as many as a dozen; I avoid these acorns for this reason. Choose the “sweetest” acorns from the list on page 37 for the least amount of work and the fewest changes of water.
Are there other methods of leaching? You bet, including outlandish ones like grinding the raw acorns into flour and hanging them in a sack set in the flush tank of your toilet—whenever you flush, it leaches more tannin out. Ingenious, but I’ll pass. Apparently Cosentino, the chef who introduced me to acorn soup, leached his in a kettle set under a gently running faucet for several days, but that seems like a waste of water to me.
One other method I like is to grind the raw acorns into flour by mixing them with some water in a blender. Blitz this until it looks like a coffee milkshake. Pour the mixture into a tall container, such as a 1-quart Mason jar or, preferably, something larger, filling it halfway. Fill the rest of the container to the brim with cool water. Seal and shake vigorously to mix. Put the container in the fridge and let it settle. Every day for a week, carefully pour off the water, leaving the flour at the bottom of the container. Add more water, seal, shake, and set in the fridge. This method takes longer, but it preserves some heat-soluble flavors and starches in the acorns. Cold-leached flour sticks to itself better than hot-leached flour, so it is preferable for baked goods. Check your flour after a week. It should taste bland, but without any bitterness or felty tannins drying your mouth. If there are any, keep changing the water until all the bitterness is gone.
Once your acorns are free of tannins, you need to dry them or they will rot. Big pieces can be patted dry on a tea towel. If it is hot out, lay the acorn pieces out on baking sheets and dry in the sun. You could also put them in an oven set on Warm for several hours.
I often roast pieces of acorn that I do not intend to make into flour. Roasting brings out the sugars in acorns and protects them from deteriorating. Roast acorns at 300°F for about an hour. Watch your acorns after about 30 minutes, however, as some species will roast faster than others, and you do not want to burn them.
You dry cold-water leached acorn flour by filling the jar with water, shaking, and then pouring everything into a colander that has cheesecloth set inside it. Let the water drain for a few minutes, then gather the edges of the cheesecloth into a ball. Squeeze it tight to get more water out, then spread the flour onto a baking sheet. Set the sheet in the hot sun, or in an oven set on Warm for 3 to 4 hours. Stir from time to time and break up clumps.
Once dry, pieces of acorn need only be put in a sealed container in the fridge, or vacuum-sealed and frozen. The dried flour will need further grinding.
Pieces can be used in a wild game soup. Ruffed grouse and acorns go well together. They are also good as nut substitutes, chopped into meatballs and as part of a turkey stuffing, or pureed in a smooth acorn soup. You might use chopped acorn pieces with venison meatballs. Deer eat acorns, and it’s a general rule in cooking that whatever a critter had been eating will go well with its meat, like pigeons and barley, duck and wild rice, and striped bass and crab, to name a few.
But as good as acorn pieces are, I prefer the flour. I normally use my strongest coffee grinder to pulverize the roasted acorn pieces. It takes about 90 seconds to turn pieces into usable flour. The rough meal you make when using the cold-water leaching method requires only about 30 seconds in the coffee grinder to turn into usable flour. You will want to sift the ground acorns through your finest-mesh sieve to remove larger pieces. Keep doing this until you have no more chunks. Beware, all you owners of grain mills: Roasted acorns could break your mill, as a roasted acorn is far harder than the hull of normal grain. And grinding unroasted acorns that have a high fat content will gunk up the mill.
Store the flour in jars in the fridge. The fat in acorns will go rancid fast if you leave the flour at room temperature.
There are many uses for acorn flour. I make an acorn flour flatbread modeled after an Italian piadina, essentially an Italian flour tortilla. Acorn flour pasta has a nutty, dark, unrefined taste best suited for rustic shapes such as orecchiette or cavatelli. Acorn pasta spaghetti served in a rich venison broth is another wonderful use for the flour. It looks like a Japanese beef soup with soba noodles.
This recipe is based on a specialty of Romagna, a flatbread called a piadina. Acorn flour makes the breads dark and nutty. Note that acorn flour has no gluten and the flatbreads will simply disintegrate if you try to make an acorn-only piadina.
Makes 6–8
2¼ cups unbleached all-purpose or bread flour
3/4 cup acorn or chestnut flour
1½ teaspoons salt
3 tablespoons olive oil
1 cup water
Sift the flours and salt together in a large bowl and make a well in the center. Add the oil and water in the center of the well and combine with a fork. When the dough becomes a shaggy mass, bring it together with your hands, then knead in the bowl until the dough picks up most of the flour stuck to the sides of the bowl. Transfer the dough to a floured surface and knead for another 3 to 5 minutes. Use a bit more flour if it is too sticky. You want a smooth, elastic dough that resembles a soft pasta dough.
Lightly coat the dough with more olive oil, wrap in plastic, and set aside at room temperature for at least 1 hour. (The dough can be refrigerated for up to 2 days.)
Cut the dough into 6 to 8 equal parts. Roll them out one at a time with a rolling pin and then your hands. You want them about 1/8-inch thick, but they need not be perfect, as this is a rustic bread.
Lightly oil a griddle or cast-iron pan set over medium heat. Cook the piadine one or two at a time for 2 to 3 minutes, or until the underside begins to get nice and brown. Flip and cook for another 1 to 2 minutes.
Keep the piadine wrapped in towels so they stay warm while you make the rest. Serve with some cheese, fresh herbs, scallions, and some high-quality olive oil.
In Puglia, Italy, this pasta was made when times were hard. It is a rough, rustic pasta that cries out to be served with mushrooms or game, or both. Ideally, you would choose wild boar, venison, wood duck, or mallard—something that actually eats acorns. In terms of pasta shape, all sorts of variations work, from hand-formed orecchiette to a thick spaghetti. This recipe is for a simple tagliatelle or pappardelle. If you want a similar effect with store-bought flour, use chestnut flour, which you can buy at good Italian grocery stores or online.
Serves 4
1½ cups all-purpose flour
½ cup acorn or chestnut flour
Pinch of salt
1½ cups cool water
Olive oil
Mix the flours and salt in a large bowl and make a well in the center.
Pour the water into the well and combine with the flours with a fork. When the dough becomes a shaggy mass, bring it together with your hands, then knead in the bowl until the dough picks up most of the flour stuck to the sides of the bowl. Transfer the dough to a floured surface and knead for another 3 to 5 minutes, or until the dough is no longer sticky and forms a smooth, elastic mass.
Lightly coat the dough in olive oil and cover with plastic wrap. Let it sit at room temperature for at least 1 hour and preferably 2 hours. Acorn flour needs a little longer to hydrate because it is coarser. This dough will also keep in the fridge for a day.
Cut off about one-quarter of the dough ball and run it through your pasta maker. Rub a little all-purpose flour on the pasta sheets if they get a little sticky. For tagliatelle or pappardelle, roll the pasta sheet through the next-to-thinnest setting on your pasta maker. Move the sheet to a floured surface and make sure it will not stick to itself, using a little more flour if needed. Cut the edges of the sheet square and roll it loosely, the way you would roll a carpet. Using a sharp chef’s knife, cut your noodles. Tagliatelle is about ¼-inch wide, and pappardelle is about ½-inch wide.
Fluff out the freshly cut pasta to separate. Dust with a little more flour. Gently pick up the pasta and twirl into a loose pile. Set aside while you roll out and cut the remaining dough.
To cook, bring a large pot of water to a boil. Add enough salt to make the water taste like the sea. Add about half the pasta to the boiling water, and use tongs to keep it from sticking to itself. When the pasta floats, let it cook for 1 minute, then serve immediately with your favorite sauce.
Eat any unused pasta soon. This pasta does not freeze well, but it will hold, gently placed in a plastic bag, in the fridge for a few days. The longer this pasta dries, the more brittle it becomes.
Acorn soup is the first way I ever ate acorns. It was at a fancy restaurant in San Francisco called Incanto, and while I never did get the chef’s recipe, I like this one even better. It is a smooth soup, deeply earthy and nutty from the combination of acorn “grits”—chopped-up pieces that have had the bitter tannins removed—and porcini mushrooms. A dollop of crème fraîche, sour cream, or even regular cream rounds everything out. Chestnuts are a good substitute if you don’t have your own stash of acorns.
Serves 6–8
1 ounce dried porcini mushrooms, soaked in 1 cup hot water
4 tablespoons unsalted butter
1 large carrot, peeled and chopped
2 celery stalks, chopped
1 medium onion, chopped
Salt
3 cups acorn bits
¼ cup pear or apple brandy
2 bay leaves
1 quart chicken, beef, mushroom, or vegetable stock
½ teaspoon ground red pepper
½ cup crème fraîche or sour cream
A few dill fronds
Soak the porcini in the hot water for 1 hour before starting. When soft, remove the mushrooms and squeeze out excess water into the soaking bowl. Strain the soaking water through a paper towel into a clean bowl and reserve.
Heat the butter in a soup pot over medium-high heat. Add the carrot, celery, and onion, and cook, stirring frequently, for 3 to 4 minutes. Sprinkle salt over the vegetables as they cook. Add the mushrooms and acorn bits and stir to combine. Cook, stirring, for 2 minutes longer.
Add the brandy and boil it hard until it is almost gone. Then add the bay leaves, stock, ground red pepper, and the reserved mushroom soaking water. Simmer gently, uncovered, for 1 hour.
Puree the soup in a blender (or use an immersion blender). If you want to get fancy, pass it through a fine-mesh sieve. Put the soup back in the pot. If the soup is too thin, simmer it until you get a soup the consistency of melted ice cream. If it is too thick, add some water and heat through.
To finish, turn off the heat and mix in the crème fraîche or sour cream. You can add regular cream if you’d like, but I like the acidic twang of the sour cream. Add more salt if needed and garnish with the dill.
