Making Acorn Meal

Acorns were a staple food for the California Indians, making up a large portion of their diet. When I first became interested in gathering and eating wild foods, acorns seemed like a great place to start. I already knew the theory of acorn processing from having studied California Indians in school and I had a ready supply of acorns out in the eastern part of the county. In school I always remembering hearing how monotonous a diet the California Indians had, eating acorn mush day in and day out so I was pleasantly surprised when I tasted acorns myself and found they were delicious! They have a buttery, almost toffee-like taste, one that my mom likens to butter brickle (I've never had butter brickle, so I can't say). The flavor is rather strong too, so adding just a small amount of acorn meal in with other flours will do a lot to add delicious flavor to your baked goods.

California Indian women considered acorns to be the gods' curse on womankind because it was so labor intensive and time spent processing acorns (a daily chore) dominated their lives. Today, thanks to modern kitchen gadgetry, the process is much easier. The process still takes a good deal of time. but neither the leaching nor drying requires much active labor. I use a food processor for initial chopping and then a grain mill to grind for the final processing into meal. If you have an especially powerful food processor that can be used for grinding grain (I believe the Vitamix can do this), then you don't need the grain mill.

Acorn harvest is between November and February in San Diego county and acorns harvested during this time will store all year, provided you keep them in the shell. Laying them out to dry before storing them away will also help them last. Traditionally they were stored with mugwort or other aromatic plants to help keep the bugs out. I didn't have any problems with bugs in the acorns I had stored this year, so if you are keeping them in your house you probably don't have to worry about this. The acorns I am processing right now were harvested last fall, and we probably have about 35 lbs of them.

What we have collected is a mixture of several species of oak, mostly Black Oak (the big, fat ones) and Coast Live Oak (the long skinny ones). This time I decided to sort them and process them separately as I have heard that different groups preferred different types of acorns. Personally, I prefer the Black Oak because they are bigger, meaning a bigger reward for your trouble, but I heard that some groups of Indians preferred the Coast Live Oaks. I'm curious to see if there is much of a taste difference between the two, which would explain a preference for the smaller, harder to process acorns.

The first step in processing acorns is removing them from their outer shells. The shell is nature's perfect way of preserving the nut inside, so I usually process small amounts at a time for immediate use. This also means it is designed to not easily open, but I find that pliers usually do just the trick. These acorns have been drying for a good part of the hear, so the shells are harder and easier to crack. When processing fresher acorns, the  shells are more pliable and less likely to crack, so a scissors can come in handy for cutting them open.

Once the acorns have been removed from the shell, the next step is leaching them. Acorns contain tannins, which give them an extremely bitter taste if eaten raw. Different species have different amounts of tannins in them, and I have heard that some species back east have very low tannin content, making them much easier to process. Traditionally the California Indian women would leach out the tannins by setting the acorns in a stream for a few days but I just use my kitchen sink for this part.

I place my acorns in a fine mesh strainer in the sink and fill it with warm water until the acorns are just covered. The smaller the pieces of acorn, the faster the tannins will leach out. You can see in the picture on the right that my pieces are not very small. This is because these acorns have been drying since January and they are HARD. They need to be soaked for an extended period of time before they can be chopped (a food processor works well for chopping), so I just start the leaching process with larger chunks and chop them smaller about midway through. Also keep in mind that although smaller pieces will leach faster, if your pieces are too small in relation to your strainer you will lose some of your meal.

I use warm water because it seems to make to process faster, but lately I have been wondering if these removes a lot of the natural oils and fats that make acorns so nutritious, so I still need to do some more research and experimentation in this area.

I don't have a set frequency for how often I change the water in the sink. This is a day long process and I am not always around all day to change the water, so sometimes the acorns will sit for hours at a time. I don't know that there is an upper limit on how frequently you could change the water. The Indians left their acorns in a constantly running stream so theoretically, you could change the water every few minutes, but I feel that this wastes water. I usually make my assessment visually based on the color of the water. The tannins come out brown so if the water comes out really dark I know it is time to change it. You can also use the color to help assess when you have leached your acorns a sufficient amount of times, as the water should come out cleaner the longer more times you change it. I usually change water around 15 times before my acorns are ready. The ultimate test however is taste. When your acorns are done leaching, there should be no bitterness left in the taste at all.

I use acorns for baking in two forms; in small, chopped pieces for use in place of nuts in nut breads and the like, or as meal to partially substitute for flour. If you plan on using them in place of nuts, chop the acorns to the desired consistency and either use them immediately or dry them for storage. If you plan to make acorn meal, there are a few more steps. 

Before the acorns can be ground into meal they need to be dried out as much as possible. I chop the pieces as fine as I can in the food processor before laying them out. I start by placing them on a baking rack covered with paper towel. The paper towel soaks up excess moisture and the baking rack allows for extra air flow. After the first day I remove the paper towel and baking rack and let the acorns finish drying on a table top. When they have finished drying, I use my grain mill to grind them into flour. 

And voila! Beautiful acorn meal!