I Gathered, Cooked, and Ate Acorns (Part 1)

Shelled acorns, sitting in a jar of water.

Ever since I was a young child, I knew that the indigenous people of northern California ate acorns from oak trees as their staple food. Acorns are high in fat, protein, and starch, and oak trees take care of themselves, so the indigenous people did not need agriculture to have a steady, reliable source of food.

As it so happens, I live near groves of native oak trees, yet it was only last year that it occurred to me that I could also gather acorns and eat them.

Once the notion got into my head, I started paying a lot more attention to oak trees than I ever had before.

Last October, I visited Niles Canyon. I noticed that, whereas the acorns in San Francisco were still immature, there were already plenty of ripe acorns in the canyon. Impatient as I was, I decided to gather lots of acorns in the canyon.

Niles Canyon – the landscape practically screams ‘California’

I had acorns, great!

Then I had to shell them and remove the tests. That was time-consuming, not in the least because acorn shells are soft … rather than cracking them off, it was more a matter of peeling them off. At least it’s a relaxing, not-mentally-challenging activity, so eventually I got a bunch of shelled acorns.

Now here is the real rub with eating acorns … they are high in tannic acid. Humans can tolerate tannic acid in very low quantities (indeed, a number of foods do have low levels of tannic acid), but acorns have way more tannic acid than humans can tolerate. On top of that, tannic acid tastes very bitter. The tannic acid needs to be leeched out.

“The Best Way to Make Acorn Flour” and “Acorns, the Inside Story” were my main guides for DIY acorn preparation. As recommended, I blended the acorns with water, made a slurry, and tried to change the water until the tannins were (almost) all out. However, I did not find their methods for changing the water entirely practical, so I ended up doing my own improvisations, such as using a baster to extract the tannic water.

Here is the acorn-water slurry. The tannic water (brown) is at the top, with a light layer of starch, with a (slightly darker) layer of acorn meal below the starchy layer.

My first attempt … I thought I had leeched out the tannins, since I couldn’t taste it in the water, but I did not taste the acorn meal itself … uh uh. The results were inedible.

I tried again. I kept on changing the water again and again and again … and it just seemed to go on forever. Eventually, I was not sure whether there were tannins left in the meal or not, but what the heck, I was tired of changing the water so much.

The acorn meal, straight out of the jar.

After pouring out the acorn meal, I used a flour sack towel to squeeze out all of the water I could.

This is what it looked like after I squeezed out the water

I then put it in a pot, added fresh water, and cooked it as a porridge. The results … there was still a faint tannic taste, but all I had to do was add a dash of cinnamon, and then I could not taste the tannins at all. It probably was no more tannins than are in foods such as walnuts (indeed, the tannic taste made me think of walnuts), so I figured it was not a health risk.

In my next attempt, I tried a different leeching method – I used whole acorns rather than blended acorn/water slurry, and rather than just using fresh water, I used a mix of water and baking soda. After a couple weeks I was getting impatient, so I tried the hot water method – boiling the tannins out of the acorns, and changing the tannic water with non-tannic hot water about every 15 minutes. A few hours later, I had boiled acorns with the tannins mostly removed (they could still be tasted, but not so much more than walnuts, so I figured it was safe). I then roasted the acorns, which made them a little firmer, but they were still fairly soft.

In addition to the acorns from Niles Canyon, I have also gathered acorns from San Francisco, so eventually I intend to shelling, leeching, cooking, and eating them as well. Hopefully I’ll get better at this process.

So, aside from edible acorns, what did I get out of all of this effort? That is a question I will answer in Part 2.