Acorn Flour

The humble acorn can produce lovely flour for baking, soups, all manner of food!

In June, my wife Stephanie and I pulled up stakes in Burbank and moved to Stallion Springs outside Tehachapi. We were immediately struck by the two great old valley oak trees in the backyard. After discovering Kawaiisu mortars on the bank of Chanac Creek less than a mile from the house and having a passing acquaintance with the Paiute and Shoshone traditions of processing pinyon nuts, I was curious if I could use the acorns that were raining down from the trees on our property.

As is my wont, I began to research and to my delight discovered that valley oak acorns are not only very big compared to other species but also tend to be very mild with regard to tannins, making them much easier to process than others. More meat and less work? I’m in. Stop it, you pervs…

I also became intimately acquainted with the acorn weevil. Specifically, its spawn. Acorn larvae. Yum! The acorn weevil bores a tiny hole in an acorn, then deposits its eggs. When they hatch, the larvae literally chew their way out. I found it fascinating. So much so that I filmed one doing just that. I’ll leave the link to It Came From the Acorn! at the end of this post for those who aren’t grossed out.

My primary resource for the project was Hank Shaw’s guide:

I opted for the cold leaching process since the ultimate goal was to attempt to bake with the flour. Here’s how it works: using a large container, place rough ground acorn meat in the bottom, then fill with water at at least a 3:1 ratio. Shake it well so the grits/flour are completely saturated. Refrigerate. We found a gallon jar will produce about 3 cups of flour so you will need quite a large capacity if you want to produce significant amounts of flour. Then, daily, pour off the water through cheese cloth, return the grits that are caught in the cheese cloth back to the container, replenish with fresh water (we used filtered), shake and refrigerate. The reason for this is to extract the tannins that create the bitter, puckery flavor you taste when you eat acorns raw. Through experimentation I found that 5 days of this process eliminated nearly all the tannins. The timing will obviously vary based on the type of acorns you have locally.

Rough ground in the food processor

Day 1

Day 2

Day 3

Day 4

Day 5

Once the tannins have been removed, you now need to dry the flour.
Hank mentioned a few methods but I found that placing flour/paste on a baking sheet worked perfectly. Setting the oven to warm (170°F), I left the flour in for 6 hours, then left it in the oven with just the oven light on overnight for an additional 8 hours. As it dried, it exuded enticing smells: mushroom, loam, cocoa. In the morning it was quite dry if a little clumpy. I placed the dried rough flour in a blender and ground it as fine as I could, then sifted it and blended the remaining rough bits until equally fine.

Fresh out of the jar and very paste-like

6 hours at 170°, 8 with oven light

What resulted was a few cups of beautiful acorn flour. The flavor is a faint nuttiness without all the deep, rich flavors from the night before. Am looking forward to producing honey cakes and a seasonal soup incorporating the flour and squash.

Acorn flour ready for cooking and baking!

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