Acorn Processing: Hot Water Bath


by June Jacobson

Acorns waiting to be processed.

In a previous post, I covered how to identify and choose acorns, with special focus on White Oaks in the Pacific Northwest. The following process uses these white oak acorns. You can use other acorns, but the processing time may be longer or shorter due to the varying tannin content.

Hot water processing is advantageous if you would like to use or preserve your acorns the same day. It takes less time than cold-water processing, but it uses more energy. The resulting nut meal may have less fat and gluten-like starch than the nut meal that comes from your cold water process, but it’s worth it if you have an immediate need.

I’ve read in online sources that you should work with the same temperature water throughout your entire process or you may “lock” the tannins in the acorn. For example, if you start with hot water, don’t switch to cold mid-process. I haven’t tested the hot to cold temperature change, but I have gone from cold to hot water when I needed the meal in a recipe right away. This went really well and the nuts only needed a couple baths to complete after a week in cold water.

There are some examples of historical acorn processing by west coast native peoples using a combination of cold and hot water methods, even the hot to cold gradation. There is one account of this method, as well as others, in the book Survival Skills of Native California by Paul Campbell, if you’re interested in some extra reading.

Steps 1-3 are basically identical to the Cold Water Process, so you can jump to Step 4.

How to Hot Water Process Acorns

The goal: remove most or all tannins from the acorn meat in short amount of time

What you’ll need:

  • nut crackers
  • cutting board and knife OR food processor,
  • two pots
  • water
  • strainer

Step #1: Crack the shells and remove the nuts

Hammer StoneDepending your acorns, they could have very thin shells or thick hard shells. Different tools work better for different shells. Here are a few tools I have used: hammer stone on a cutting board, good quality nut crackers (the painted Christmas kind usually lose their head with the first nut), hammer and a towel on a cutting board.

My favorite method is using a smooth, rounded rock that fits into the palm of my hand called a hammer stone. I lay the acorn down on the shallow mortar made by a friend of mine or a cutting board and I bop it. This works great for the skinny, thin shelled acorns that seem to just bend with the nut crackers.

Step #2: Inspect

A fresh nut should be a golden brown color, although it may change to a more gray brown as it dries. If you see a little pink hue on parts of your nut, it means it is starting to germinate, and getting ready to sprout. That is okay. In fact, some folks are starting to use sprouted acorns in recipes. They claim that the nuts are sweeter and easier to digest since the nut starches have started to turn into sugars. Taste test a nut so that you know what you’re starting with. You’ll be taste testing throughout and it helps to know what progress you’re making.

Throw your nuts into a bowl of water after removing the shell. Fresh or lightly dried nuts may start to change color the longer they sit out, much like a cut potato will darken. The darker brown lines and color change is caused by exposure to the air and can ultimately affect the flavor if left to dry out too long outside the shell.

Step #3: Make a Course Meal

Once you’ve shelled the nuts you want to chop them on a cutting board with a knife into a coarse meal. If you have a food processor, drain them and process them for just a second or two. The larger you chop or process, the longer it takes to remove the tannins, but I’ve noticed that you retain more fat and nutiness. It’s a trade-off.

Step #4: Start Hot Water Bath

Pour your bowl of acorns into a stove pot and make sure the pot has at least twice as much water as nuts. While bringing your nuts to a boil, start a second pot of water to take it’s place after the first hot water pot boils for 20 minutes.

Step #5: Strain nuts and Repeat

Strained acorn mealAfter your acorns have boiled for 20 minutes, strain the nuts and pour them into the second pot of already boiling water. Fill the first pot with water and start the boiling process again. You can always save your first few water baths for a tannic solution for hide tanning, anti-fungal foot wash, or shampoo.


Step #6: Repeat Water Bath To Taste

Keep repeating steps #4 and #5 until you have a nut that meets your taste needs. The white oak acorns I use can take 4-5 baths before their ready.

You should be all set to start your processing. Remember, this is a great project for friends and family, especially if you include a hammer stone for the kids! Have fun, good luck and let me know if you have any questions.