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Manna from heaven?
There are thousands of pounds of food up there.

As a native perennial species that has adapted to the land and climate
of the region, oaks are a sustainable food source if there ever was one.

By Andrea Riordan
Photography by Kodiak Greenwood and Ken Payton

It’s August, and the landscape is parched. I’m standing under a valley oak tree outside of Salinas on a drive down to Los Angeles from my home in Santa Cruz. In spite of the dryness everywhere, this tree, which could be up to 300 years old, is laden with a formidable feast. The subtle jewels in its canopy haven’t browned yet, but they number in the thousands.

Worldwide, there are more than 500 species of oak, or Quercus in Latin, and all but a few bear edible fruit. California is home to 15 different oaks, and Central California can claim six of those. The most dominant here are coast live oaks, which are evergreens with spiky leaves, and valley and blue oaks, which are deciduous and have lobed leaves.

As a native perennial species that has adapted to the land and climate of the region, oaks are a sustainable food source if there ever was one. And that both makes them attractive to foragers, and begs the question of whether or not they might be a tree worthy of cultivating for animal forage or food for humans, as native Americans did.

The biggest goals in sustainable agriculture are soil conservation, water conservation and reduction of chemical use in the fields, and oaks are drought tolerant and can grow on land that is normally non-arable.

David Bainbridge, retired associate professor of sustainable management at Alliant International University in San Diego, says that while a continuous commodity corn crop in the Midwest U.S. loses an average of 89 tons of soil per acre per year, an oak forest will only lose four pounds and can produce up to 6,000 pounds of acorns.

When it comes to water use, California’s almonds well known for their big irrigation needs and use one gallon of water per almond grown. An established oak, on the other hand, uses deep water tables and is actually intolerant of irrigation.

The stress of industrial farming on bee colonies is well known, and the future of America’s bee population is under great threat. Oaks are not only wind pollinated, meaning they don’t require the help of bees to set fruit, they also provide beneficial habitat for insects and other fauna. According to the Resource Conservation District of the Santa Monica Mountains, a single oak can host more than 5,300 different species of bugs, animals and other creatures.


In the kitchen at Sue’s Acorn Café and Mill: Chin
processes up to 700 pounds of acorn flour each year


The vast oak groves that now grace one-eighth of California may seem like wild arboretums, but it turns out they were often cultivated in a synergetic combination of efforts between native tribes, squirrels, jays, woodpeckers and foraging mammals.

For instance, contemporary oak pests, such as the California oak moth and acorn weevil, were curbed by native peoples through careful fire management. The ashes from the fires also created fertilizer, says Tamara Wilder, a Northern California wilderness skills expert. Still, there are reasons why oaks aren’t commonly cultivated for their acorns.

Most challenging is the fact that an oak tree can take anywhere from 12 to 30 years to mature—an extremely long time from an agricultural standpoint. By contrast, almonds mature to production at about four years. Oaks also exhibit mast behavior, which means in some years, they are prolific producers of acorns, and in others, they are abysmal, making acorns an unpredictable crop.

“It’s an abundance culture, which we tend to be uncomfortable with because it’s not as easy to control,” says Shawn Overstreet, a Ph.D. candidate at UC Davis, who is exploring the history and potential future of oak tree propagation and acorn harvesting on a commercial level, mostly for livestock fodder that could replace industrially produced soy and corn.


The acorn harvest season lasts from September to November, and all that must be done to collect them is keep an eye out and pick them up from beneath the trees before they spoil or insects and animals get to them.

Acorns contain bitter tannic acid, which helps preserve them once they’ve been harvested, but it needs to be leached from the nut before cooking.

Native tribes in California had many different processing methods, depending on the type of acorn being used and what the recipe was.

Valley oaks, which are part of the white oak group, have very little tannic acid. Live oaks, part of the black oaks group, are notoriously bitter with it but are reputed to have the best flavor once leached.

The most common preparation method was to harvest the acorns and dry them in the sun until the nut inside pulled away from the husk. The acorns could then be stored in special baskets or bins until they were ready to be used.

Dried acorns would be cracked with a stone and the nuts shaken in a type of winnowing basket to rub away the papery skin that covers the meat. After the nutmeat was pounded to a meal, it would be placed inside a cloth and put either in a running stream of water or put through changes of water until the bitterness was gone. (See also “In Search of the Real Paleo Diet: Remembering the Esselen people of Big Sur, EMB Fall 2014.)

There is little record of what was done with the tannic water used to leach acorns. But today the water can be put back into the soil or, if you’re the homesteading type, used to dye cloth, tan hides, wash clothes and, as local lore has it, cure poison oak rash.

Acorns were the main food source for many native Californian tribes. The meal was made into unleavened cakes, soups and gruels and pounded into pemmican. Like most meals and flours, it readily takes the taste of whatever it is cooked with.

Acorns are also highly nutritious, and flours made from them, like other nut flours, are gluten free. A pound of shelled acorns yields 1,265 calories, and the nuts are high in carbohydrates, fat, vitamin B6, magnesium, potassium and calcium.

John Muir once said acorn bread was “the most compact and strength-giving food” he had ever eaten.


To see a modern acorn enterprise, I visit Sue Chin of Sue’s Acorn Café & Mill, an online acorn flour shop.

As I drive to her storefront in Martinez, I wonder if I’ve reached the wrong place as the sign on the front of the pink stucco façade reads: The Hot Dog Depot.

But as I walk inside the small restaurant Sue runs with her husband and son, I see on the counter a narrow row of acorn flour pastries: muffins, rolls and biscotti. In the back, past the mustard and mayonnaise tubs, are bins of acorn meal Sue has processed by hand. A Korean native, Chin began her acorn enterprise several years ago, after someone gave her some acorns.

“When I was first gifted the acorns, I tried to make the traditional Korean acorn starch jelly, dotorimuk, but I realized there was so much waste and extra labor to extract only the starch. I had heard that there were other traditional ways of preparing it, so I began experimenting,” Chin says.

Over the last eight years, members of Chin’s church community and other Martinez residents who have caught wind of her endeavor have offered her hundreds of pounds of acorns from their valley oak trees. Chin’s advanced age and diminutive figure defy her strength.

She processes up to 700 pounds of acorn flour a year and has started selling it to restaurants as far away as New York City as well as locally to Sierra Mar at Post Ranch Inn in Big Sur. To demonstrate, she takes the coarse meal she has dried in a 200° F oven and puts it into a Vitamix to make a fine flour.

“Now, I make American-style treats with half white and half acorn flour, but I don’t eat them,” she says with a smile. “Too much sugar for me.”

I do eat them, and I find that the biscotti shows off the flavor of the acorn flour particularly well.

Alliant International University’s Bainbridge believes that the market is ripe for new experimentations like Chin’s.

Acorn oil, for example, could be as successful as the Moroccan argan oil frenzy six years ago.

And acorn flour could be made into tortilla- style chips. The sweeter nutmeats could be candied and sold as snacks.

All around the world, the acorn holds great cultural and gustatory significance for peoples who live among the oaks. In Europe and North Africa, for example, acorns are still served at farmers’ markets as whole, slow roasted nuts much as chestnuts are in parts of the United States.

In Spain, the acorns, called bellotas, are germinated and fermented into a liquor called licor de bellota and are credited with giving the famed jamón ibérico its vaunted flavor. Here on the Central Coast, we have an opportunity to take another look at the acorn and think of it not just as a wild food to forage, but potentially as a sustainable local cultivated crop. Oh, the possibilities.


Acorn Cornbread

Acorn Pate

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At Edible Monterey Bay, our mission is to celebrate the local food cultures of Santa Cruz, San Benito and Monterey Counties, season by season.