Master the Technique of Making Acorns (Oak Nuts) Edible

Tip to make acorns (oak nuts) edible
We often see squirrels, deer, and other animals feasting on acorns, but have you wondered if we humans can eat them? Yes, they are edible, provided you take efforts to eliminate their toxic bitterness. Buzzle will guide you through the process and methods involved to make them edible.
The Right Pick
All acorns contain tannin in varying concentrations, which makes them bitter and toxic if consumed in large quantities. But, white oak nuts, naturally, have less tannin than black/red oak nuts. A small but vital tip is to pick acorns that have smaller caps because the bigger the cap, the more bitter the acorn.
Acorn or oak nuts are fruits obtained from oak trees. The unripe nuts are green in color, and the ripe ones are brown. The smooth and tough shell of the nut contains a single seed, which has a cap (cupule) on it. They are quite small and are in the range of 1 - 6 cm long and 1 - 4 cm broad. These nuts take almost 6 - 24 months to mature, which depends on the species of the oak tree.
It's a very popular food among the animal kingdom, so much so that acorns have been depicted on the silver screen too. Remember the squirrel from the Ice Age series? Yup, it is desperately trying to secure an acorn.

Back in the real world, the abundance of oak trees is a boon for all the mammals and birds who eat them. Some woodpeckers, pigeons, ducks, squirrels, and mice feed a lot on these nuts. Pigs, deer, and bears are also seen to feast on them. But acorns are not very safe for cattle and horses, because they turn toxic if consumed in large quantities. The same is applicable to humans too. We do have an advantage though, we have found out ways to decrease their toxicity levels. How? Here's some information on that.
Note: Acorns should not be consumed raw. If you're trying them for the first time, eat a very small quantity to check whether you are allergic to them. If you observe no allergy signs or symptoms, then go ahead and eat more!
There are over 400 species of oak trees but are divided in two basic types: white oaks and black/red oaks. Here is Buzzle's detailed post on identifying the oak leaves which is vital for identification of the edible and non-edible acorns. Sticking to the two basic types found in the U.S., here's a brief explanation on how to identify them.
Know the Trees Well
Red/Black Oaks
Red Black Oak Edible
These oak nuts take lot of time to mature and grow. They fruit almost after two seasons. You can identify these trees by looking at the leaves that have pointed ends and prickles at their tips. The nuts may have hair on the inside of the caps. These nuts contain more tannin, which gives them a more bitter taste. Hence, they need to be processed before they become edible.
White Oaks
White Oak
White oak nuts grow at the end of the first growing season. The leaves of these trees have round, lobed ends which have no prickles at the tips. The nuts are quite sweet to taste, because they contain very little amount of tannin. A unique characteristic about white oaks is that if one tree produces a good yield, then a same species tree in the vicinity will also yield well. This feature is not observed in the black oak trees.
Collection and Selection
The collection starts in September and ends in October as the acorns fall to the ground. Be extra sure that you choose all the brown and ripe acorns. Green acorns are unripe, and can be toxic. You can collect green ones and store them till they turn brown. Check for any holes or molds that may signify a worm infestation.
Removing the shells
Removing Caps of Acorns
The next and important step is to remove the caps. Crack the thin outer shell with a nut cracker or pliers. Also, check that the acorns should be firm and without any mold or holes. Only then can they be processed further. But, do not remove the nutmeat shell (inner shell) until you decide to cook them.
Always carry out this test. Dump all the acorns into water and observe. Acorns that float should be discarded, and those which sink should be used. You can later dry them in an oven or in the sunlight to remove the moisture in them. We have to leach them so till then, they need to be dried thoroughly to prevent mold growth.
Leaching Process
There are three ways of leaching acorns. Each way has its advantages and disadvantages. For leaching, you need to remove all the shells so that all you have is the nut meat.
edible leaching oaks
1. Place them in a stream
This is a method which was used in the olden days. Nowadays, we hardly get clean water so this is the least used method. Basically, all the acorns are tied in a cloth and held in a running stream for many days. The running water washes away the tannin acid.
2. Soak in cold water
Soak all the nuts in a bowl of cold water. The water turns brown because of the tannin acid. Keep changing the water until the water remains crystal clear. This method makes the nuts bland and the meal thickens, so they are best used in making flour.
3. Boiling method
This method is commonly used but has been a matter of confusion. It will remove all the bitterness but sometimes, it may attach the tannins to the acorns. Also, it may boil the oil which will reduce the nutrition to a large extent.
The process requires you to have two boiling pots. Dump the acorns in the first pot of boiling water and soak them till their color darkens. After that, remove the acorns from the first pot and soak them in the second pot of boiling water. Repeat this process till the color of the water doesn't change. This process is ideal when you just want to eat roasted nuts.

Note: In this process, make sure that you never put the acorns in normal or cold water because this will reattach the tannins. Always shift the acorns from one boiling pot to the other. Also, don't start boiling after the acorns are in normal water because this will make them bitter.

If there is bitterness even after leaching, you can soak the acorns in milk for sometime and then just pour off the milk.
➤ Acorns can be consumed when roasted or simply dried.
➤ You can also make candies by coating the nuts with sugar. Also, you can pickle them in a salt solution.
➤ In the olden days, acorns were a cheaper alternative to coffee beans. You can also try making coffee from acorns because you get these nuts for free.
➤ Ground acorn flour can be used in breads and cakes. In some dishes, it can be used for thickening sauces and gravies.
➤ Acorn oil can be made with the less bitter nuts. Some say that its taste is similar to olive oil.
You can also store these "free" nuts for a long time, while they are raw. But that also depends on the type. White oak acorns can perish quickly. Whereas, the tannins in the red/black oak acorns prevent the attacks of bacteria/fungi, which make them last a lot longer.