Tuesday, May 20, 2014

Acorns for food, a nutty idea

Here's an odd food idea by Dawn Starin of Scientific American I originally included in Overnight News Digest: Science Saturday (West Antarctic ice sheet collapsing): Is Reintroducing Acorns into the Human Diet a Nutty Idea?
If harvested sustainably and treated to remove bitter tannins, acorns may once again have a more prominent place in the kitchen

As the world’s breadbaskets strain to meet the demands of the Earth’s growing population, already more than seven billion strong, we could use another nutritional, ecologically friendly food source. Could acorns, the fruits of the oak tree, be the answer? Certainly, they are beginning to draw renewed interest in the hunt for sustainable alternative food sources.

Over the past decade various Web sites, magazines and newspapers have recommended that the occasional acorn-based items be reintroduced into our diets. With a growing interest in foraging for local, edible wild plants, eating new and ever-more exotic food items and the need (both real and imagined) for gluten-free ingredients sweeping through parts of the Western world, is it possible that acorns—small nuts that fit all of these criteria—could be on the verge of a dietary comeback.
More than 15 years ago, I read Jared Diamond's "Guns, Germs, and Steel," where the idea of domesticating oaks was discussed and dismissed.  Here is the reasoning from enotes: Why were almond trees domesticated for consumption but oak trees were not?
Basically, the answer is that bitterness in almonds is controlled by only one gene.  In oak trees, by contrast, the bitterness of acorns is controlled by many genes.

The reason that this is important is because this means that about half of the almonds from a tree that is not bitter will also produce trees that are not bitter.  By contrast, almost all of the acorns from a "good" oak tree would (if you plant them) produce an oak tree whose acorns are bitter.

This means that it would be much easier to selectively breed good almonds than it would be to breed good oaks.  Therefore, people would quit trying to domesticate oaks but would continue to try to domesticate almonds -- they would have a much better chance of success with the almonds.
Also, I recall that Diamond argued that oaks have long generation times and the selection pressures humans were capable of putting them under were less than that of the wild animals that normally eat acorns.  Still, if one could reduce the bitterness by a more expeditious way than grinding the acorns into flour and then leaching the tannins out of them for more than a day, I suppose it could work.  However, oaks will likely remain a wild-collected food source, like morels and truffles, for at least a century, even if they can be successfully turned into food for modern humans.


  1. 10,000 years ago, acorn mush was cooked in baskets, using hot rocks.

    1. As it was still done by the Native Americans of California until 150-200 years ago.