Birch oil is a resource that has been used by humanity through much of our history. It can be used as fuel, to make a primitive glue/pitch for making seals or to attach arrow heads, it is a very effective mosquito repellent and can also be used as medicine. It's very versatile.
The easiest way to extract the oil is to dry distill the birch bark. It is both simple and fun and can be done with simple means.
What you need:
- 1 larger tin can with lid
- 1 smaller tin can without lid
- Dry birch bark
This is how it's done:
Obtain two empty metal cans of which one has a tight fitting lid. Paint cans work well for this. It is best if the two cans are close to the same diameter because the idea is to create an oxygen-free environment for the bark. Of the two cans, the smaller one should be the one without a lid.
Make a hole in the center of the bottom of the larger can. (The easiest way to make your hole is with a hammer and nail.) A hole of about 2-3 mm in diameter is enough. Make sure you make the hole from the inside of the can so that you make it easier for the oil to flow into the bottom can.
Cut your birch bark so that when it stands at the top of the large can, it is a bit shorter than the height of the can. Roll the strips and place them vertically in the can - make sure you do not cover the hole you made in the bottom! When all bark is tightly packed, put the lid on and close it properly.
In the middle of your fireplace you dig a hole deep enough so that your smaller can (collection can) stands at or slightly below ground level.
Place your collection jar in the hole, ensuring that it is stable and even. Be careful not to get dirt in the jar! Now place the top can with the lid on so that it sits directly on top of the collection can. There should be no air holes - remember we want an oxygen-free environment.
Use soil to gently create a light seal around where the two cans meet. Not so tight that you seal in all the gases, but enough to hold the two cans in place so that the top can does not fall or you get dirt in the collection can. The collection jar should be completely covered at this point.
Start a fire over and around the upper can and keep the fire burning for 1-3 hours. It does not have to be a big fire, but should cover the can well from all sides.
Let the fire burn down and as soon as it has cooled down, gently scrape away the ashes and the dirt around the two cans, be careful not to let dirt or ash fall into your precious oil.
Using pliers or gloves, remove the top jar and get a look at all the beautiful birch oil that have been collected in the bottom jar! After the top can have had a chance to cool off, carefully remove the lid to see how much remains of your original birch bark strips.
At this time the oil can be used for waterproofing clothing, treating wood and to makemedicine. With some refinement you can easily create fuel, other useful medicines and binders such as primitive glue or pitch.
To thicken the oil into something more tar-like, you only need to boil the oil to remove any volatile (flammable) substances. Boil slowly over low heat for about an hour until it becomes quite viscous and is about half of the original volume. When the tar has the desired consistency, remove it from the heat and let it cool.
This material can now be stored and used indefinetly!