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Processing and storing acorns has a lot of mystique surrounding it. The process that follows comes from Marcie Mayer (who I interviewed for my podcast – listen here) and has been developed over 20 years.
How to Dry and Store Acorns
- Always gather your acorns green. This way the acorns are likely not to have been infested by larvae, beetles and rodents.
- Take the acorn out of the cup and lay flat in single layers on a drying sheet, tabletop and allow to dry. They are ready when they sound like they have a bean inside them.
- Store the dried acorns in their shell in large buckets with an airtight lid.
- The secret is to get them very dry and store them in their shells because the tannin is a natural preservative.
How to Process Acorns: Method 1
- You can either process acorns fresh (green shell) or dried (brown shell).
- First, you need to remove the nut from the shell. The easiest way is to split them in half using a knife. Then pop the nut out.
- Discard any damaged nuts.
- Put the nuts into a food processor with enough cold water to cover. Never use hot water at any stage when processing acorns. Then pulse until you get a mash, next pour the mixture into a large jar or bucket.
- Place the jar under a tap (or use a hose) and allow the water to circulate and gently overspill for between 1-2- minutes. Slowly stir the mixture. While doing this make sure the mash doesn’t come out.
- Pour off the water and refill one last time. Then cover the jar to prevent dust and insects entering.
- Each day, pour off the dark tannin water and refill. Make sure you don’t pour away the fine starch in the bottom of the jar or bucket. Refill with cold water.
- Stir twice a day throughout the leaching process.
- Acorns can take anything from 2 to 10 days to remove the tannin depending on what species of oak used.
- Once the leaching is complete. Spread the mash in layers no thicker than 1 cm on a baking tray. Then place in an oven at the lowest setting leaving the door slightly ajar.
- Turn the mash every hour breaking up any clumps that have formed. Once dry (takes around 12 hours) cool before storing in sealed jars.
- Blend the mash until it becomes flour. The flour will store in sealed bags in the freezer for up to 2 years.
How to Process Acorns: Method 2
- Slice each acorn in half, and pop the nut out into a bucket. Fill with cold water and cover to keep dust and insects out. Stir twice a day.
- Each day pour off the water and replace with fresh cold water. Repeat until the nuts taste sweet and you feel most of the tannin has been removed. Acorns leached this way can take anything from 2 to 14 days to remove the tannin depending on what species of oak used. Let your tastebuds tell you when they are done.
- Once leached spread out the halved acorn nuts in single layers on sheets and dry in a low-temperature oven leaving the oven door slightly ajar. Takes around 12 hours, maybe longer. Or dry in a dehydrator.
- When completely dry, place in halved acorns in an airtight sealed container and freeze for later use.