Why leaching acorns?
For thousands of years, acorns have been a valuable food source for humans. However, consuming them directly from the tree can be unpleasant due to their bitter taste.
This bitterness is caused by tannins, which can have an astringent effect on our taste buds and even lead to kidney damage over time.
To make them edible and palatable, acorns must be leached in a process that involves soaking them in water to remove the tannins. Once this process is complete, the acorns become completely safe to consume and are actually quite delicious and nutritive.
In this post, we’ll explore the ancient technique of acorn leaching and how it can be done at home.
Before you start leaching acorns
There are quite a few ways to leach the tannins, but it can be summarised into two: cold leaching and hot leaching. The method you want to use is determined on what you want to do with the acorns afterwards.
The temperature at which you process the acorns is important. Boiling or roasting precooks the starch and therefore cannot be used as a binder in any recipe. On the other hand, cold leached acorn meal will thicken when cooked, as eggs would do.
Hot leaching is recommended for making roasted acorn snacks, burger patties, mock coffee, brittle, or adding to stews. On the other hand, cold leaching is more appropriate for producing baking flour. However, hot leached acorns can still be used for baking by adding extra binder.
Before leaching, it is necessary to remove the acorn shells. You can use a pair of gloves and a sharp knife to cut the husks and extract the meal. If you plan to use them as flour or coffee, it is okay to chop them into quarters. This method makes it easier to cut and dry the acorns faster than using whole acorns.
Cold water leaching for acorns
In nature, squirrels bury acorns in the ground, leaving them for extended periods, allowing rain and running water to naturally leach them. This method tries to replicate it in a controlled environment.
First, crush the acorns into small pieces or grind them into coarse meal to accelerate the process. It is essential to remove as much brown skin as possible before grinding, as it is quite bitter.
Next, soak the chopped acorns in several changes of water until the water runs clear or the acorns no longer taste bitter. Repeat this process multiple times, and do not let the mixture stagnate for more than a day, as it can spoil.
Alternatively, you can place the chopped acorns in a muslin or cheesecloth over a basket in your sink. Gently massage the cloth and keep the water running until the acorns are no longer bitter. This method is quicker but may result in some flour and oils leaking with the movement.
Now, the acorn meal is ready to use as baking flour, which requires further preparation.
Hot water leaching for acorns
By following this method, the tannins and the natural oil will boil off, resulting in a sweeter flavour.
Begin by placing your shelled acorns in a pot with cold water and salt. Bring the mixture to a boil and let it simmer for 30 minutes. As the acorns cook, their skins will detach and float, making it easier to remove them with a skimmer. In the meantime, prepare a second pot of boiling water.
Once the water in the first pot has darkened, pour the acorns and water into a colander and transfer the hot acorns to the second pot of fresh boiling water. It is important to never place the acorns in cold water, as this will bind the tannins, leaving them bitter. Repeat this process by changing pots for a third and fourth time, and the acorns will be ready as soon as the water runs clear.
Leached acorns can be used immediately in your desired recipe or dehydrated, pickled in salted brine, or frozen for future use.
Is it really worth the effort to leach acorns?
At this point, you may be thinking that the process of leaching acorns involves a lot of work. And indeed, it does require time and effort. However, foraging is not only a way of sourcing food, but it’s also a lifestyle. By foraging and preparing your own food, you are able to experience new flavours, learn new skills, and utilize nature’s resources.
Acorns are a prime example of a food source that is often overlooked but is incredibly nutrient-dense. They contain a high amount of starch, which can be difficult to find when foraging. By taking the time to leach acorns, you are able to unlock their nutritional value and transform them into a versatile ingredient that can be used in a variety of recipes.
So while leaching acorns may require some effort, the end result is well worth it.