How to Make Flour From Acorns

 How to Make Flour From Acorns

Why would you want to make flour from acorns? 

Taste, that’s why.

If you have done any searching on the internet for making acorn flour you will quickly notice that there are many different methods that people use. This  is purely down to the equipment that they have and the type of acorns that they are working with. Yes, there is more than one type of acorn!

I encourage you to try more than one method out to see which one works best for you. Get creative and don’t be afraid to experiment!

Before we start we need to gather together some supplies. Go ahead and grab the following:

  • At least 1 gallon of large freshly fallen acorns. This may seem like a lot but it won’t be worth the effort if you go for any less
  • Cooking sheets
  • Mallet or hammer and towel to crack the acorns
  • Something to grind them such as a flourmill, food processor, or potato masher.
  • Sifter or pasta strainer

How to Make Flour From Acorns

When choosing your acorns, the bigger, the better! 

Once you have gathered at least 1 gallon of acorns, you will need to separate the good ones from the bad with what is known as the “float test”.

Float Test

Place your acorns into a large pot and fill the pot up with water. Remove any acorns that float as these will be the bad ones or the ones that have acorn weevil larvae in them.

Flash Boil

Acorns will start to turn bad fairly quickly if you leave them in your bucket for too long so be sure not to leave them for any longer than a couple of days. If you can’t process them within this time you should plan to dry them by putting them on dry racks or cookie sheets in a dry, sunny spot inside or outside immediately after collecting them.

It can take anywhere between 7 days to several months to fully dry your acorns, depending on the type that you have which is why it is much better to just crack on and process them when you get them.

Next you need to prepare your acorns to be cracked so bring a pot of water to the boil and once the water has reached boiling, flash boil your acorns for around 30 seconds. Any longer and you will cook the acorns which we don’t want. This step is purely to help you with cracking and separating them from their shells. Start cracking your acorns while they’re still warm.

Cracking Your Acorns

If you don’t have a proper nut-cracker, a simple mallet or hammer will work to crack your acorns.

Place rows of your acorns onto a towel, fold the towel over on top of the acorns and work your way down the rows, cracking each set of acorns with your hammer or mallet as you go.

If your acorns are of a variety that have a thick skin on them, you will need to remove those with the help of the oven during drying.

Drying Your Acorns

You have three options for drying your acorns. You can either:

  • Put your acorns on sheets to dry in the sun,
  • Stick them in a dehydrator, or
  • Bake them in an oven on 250 for about 20 minutes (whichever option is easiest for you).

This will ensure that everything dries out, which will cause the nutmeats to shrink, and their shells and skins to separate from the meats with minimal effort on your part.


Removing the shells and skin should be a lot easier now that you have dried the acorns and they should separate by simply rubbing them in your fingers.

Put all of your clean, dried acorn nuts in a bowl. Dispose of the skins and shells. You should now have a bowl of clean acorn nut meats with no shells or skins.

Leaching to Remove Tannins

It is up to you whether you go for a cold leach or a hot leach to remove the tannins in this step.

  • Hot leaching – faster but removes more of the water soluble nutrients in the nuts than cold leaching. This also breaks down the glutenous properties of the acorns. This means that it won’t be as good for making baked goods that stick together similar to wheat flour baked goods.
  • Cold leaching – I found a great article about cold leaching over on Backyard Forager which you can read here as it is beyond the scope of this guide.

To hot leach your acorns, bring a large pot of water to the boil and once boiling, add your acorns and let them lightly boil for about 1 hour, strain them in a colander and repeat this process as many times as needed until all of your acorns are done.

Do NOT put your acorns in cool water at any point. You should only add them back to a fresh pot of water once it’s boiling, or you risk the bitter tannins locking up in the nutmeat.

There is no way to know exactly how many flushes of boiling water it will take to remove enough tannins from your particular variety of acorns so you will have to taste-test them after each draining. Once there is no bitter taste in the acorns, they are ready. Leave to cool slightly before moving to the next step.

Mash Them Up

Start off by placing 2-3 cups of acorns at a time into a large mixing bowl and using a potato masher, mush the acorns up into a moist yet powdery texture by pressing down then turning with the masher. If you have a food processor you could make it much easier by using that instead and add just enough water for the processor to blend the mixture into a fine pulp.

Once mushed up, spoon your acorns onto drying sheets to be placed into the sun, low baked in an oven, or into a dehydrator. Once they are completely dried out you can move on to grinding.

Grinding and Sifting

I applaud you if you have stuck with me this far but finally we are at the last step.

Once your acorn mush has completely dried out place batches of it into a food processor and grind it on the highest setting possible for 1-2 minutes. Stir and repeat.

Place your pasta strainer over a large bowl and pour your pulverized acorns into it and sift. The fine flour will sift through into the bowl with just the acorn grits being left in the strainer.

Store in an airtight container in a dry, dark cupboard, a fridge, or a freezer.

I would absolutely love it if you got this far and can send in your pictures to our Twitter so we can check out your work!

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