It has been a productive autumn and you harvested loads of acorns. You may not know what to do with them or how to process them to make the nuts edible. I am going to explain the leaching process that will remove the bitter tannins that make raw acorns inedible.
Extracting acorn meal
You will need to extract the acorn meal first and it seems that shells get soft when left in water for a while. Use a very sharp knife and a folded kitchen towel to avoid the nuts moving around when chopping them up. This will also avoid a kitchen accident.
It will not be easy to shell the acorns and patient is required. However, when using the nuts to make flour, it’s ok to chop each acorn in half to then cut the halves into quarters and collect all the meat inside. Keep them in a bowl of water to prevent oxidization.
You can store them for months by thoroughly drying or roasting the acorns and storing them in jars. After you extract the meat, you need to remove tannins to make them edible. Tannins are water soluble compounds and there are mainly two methods to leach acorns: in hot water or in cold water.
Cold water leaching
Cold water leaching is the best one to choose, especially when making acorn flour. Nutrients will not be removed and starch is preserved: that will help to hold the “dough” together when shaping bread and cakes. Flour will also be paler.
Chop or grind your acorns into small pieces, as it makes a lot easier to leach the flour. Ideally, running water removes the tannins. You can leave the acorn meal in a bowl of water and change several times a day, till water is clear and bitterness is gone.
Hot water leaching
Hot water leaching seems to bring out the nutty flavour and it is best for sauces and savoury dishes. You don’t need to chop them first, as you can use big chunks for specific recipes. Please note that you will boil off the oil, reducing their nutrition.
Boil the acorns in several changes of water (three were enough to me) with salt until tannins are removed. Do not add fresh cold water, as the bitterness will be locked into the acorns. Make sure you dry the acorn meal before using.
It may sound like a hell lot of work, but it’s not that much, especially in good company. It does really worth every second spend at the process. At the end of the day, you will have a unique dish with a surprisingly good result. After processing, it is very easy to store and really versatile.