Saturday, October 31, 2009

Oak trees and acorns

Quercas garryana of the family Fagaceae. The beech family.

Garry oak can be found in dry climates, lower elevation, on rocky bluffs and slopes. A heavy limbed tree up to 25m it may be short and crooked in rocky habitats. 

Light grey bark with thick, deep furrows and ridges. the trees normally have a dense rounded crown but tops may be narrow and irregular when found in stands. 

The flowers are tiny and incospicous appearing in spring with the leaves. Both male and female flowers grow on the same plant with males in long hanging catkins ,  females in small clusters

The leaves are alternate,  decidous and lobed,   12 cm long, shiny, leathery, dark green on top, lighter and velvety or hairy on the bottom.

The acorns are ripened and falling early to mid fall but the bark can be harvested year round
The best way to harvest acorns is with friends!
In Washington, where I live there are a few Oaks which grow but Garry oak is the most wide spread and it is nice to work with as an edible because of its relatively low tannin content. There are three types of oak: white, red and black. all are edible but black and red have high levels of tannin in their acorns. This isnt a bad thing per se it just requires a bit more preparation to be palatable. The tannins have many medicinal properties so generally speaking, if you are harvesting for food white oaks have a slight advantage but if you are harvesting for medicinal use red and black have an upper hand. 

There are some easy ways to tell the difference between a white oak and red or black oaks

white oak:
rounded leaf tips
lower tannin
cream colored nut meats
smooth inner shells

red and black oak:
pointed leaf tips
high tannins
yellow or orange nut meats
fuzzy inside the shells

Good harvesting etiquette is to pick the acorns that have already fallen. This also ensures you the highest ration of ripe fruit. While collecting or after you have your full harvest, inspect the acorns for any obvious rotting or molding or small holes that are indicative of insect infestation. If the acorns are not going to be processed immediately after collecting they need to be dried or frozen. Some options for drying are in the house at room temperature, in the oven with very low temperature, in the sun, next to a fire or with a food dehydrator. There are pros and cons  to each method but for long term storage without freezing they must be dried. After drying acorns should be inspected once or twice over the 2 weeks following drying to double check for cracks, holes and molding.

When the acorns are ready to be processed, whether fresh, frozen or dried, remove the knurled crown from the top of the shell and then break open the shell to remove the nut meat. Anything hard will crack open the shell of course but I am now biased toward the traditional method of using a stone implement.

Not only is stone free but there is a nice practicality to it. The shapes are right  and there is a nice elegance to it. The stones feel right and their weight helps you appreciate the reward you are working for. It is not hard work, very meditative and very satisfying.

There will be papery skins over the nut meat which should be peeled away. Once the nut meat has been seperated the tannins must be leeched. Poor the nuts into boiling water and boil for 5 minutes. the water must be boiling or it will take much much longer for the tannins to leech out. For red and black oak the boilling process may need to be repeated once or twice. It should be repeated with fresh water since within 5 minutes the tannin content in the water has reach equilibrium with the nuts and no more leeching will happen. Adding a bit of canning salt to the boiling process will prolong the acorns shelf life.

In a wilderness or survival setting the water might not be saved and  boiling may not be an easy option. In such cases the acorns can be leeched by soaking the nuts in running water like a river or stream for several hours. Another method is to grind the nut meat and pour boiling water directly over the meal. One brilliant method involves digging a hole in the sand and pouring the ground nuts into the sand. Cover the hole with pine boughs and pour boiling water over the grindings. A gelatin film will develop between the acorn meal and the sand and the meal can be carefully scraped up without getting any sand mixed in.

If possible do not pour out the water! While not at all tasty, the tannins have many medicinal and utilitarian uses. tannin is a strong astringent and antiseptic. The tannic water can be reduced and used for mouth rinses, dying, tanning and laundry detergent. Tonics can be used to treat burns, diarreah, hemorrhoids, dandruff, boils and a host of other medicinal uses.  Another element leached out is quercin. quercin will bind with skin proteins to speed the healing process for cuts, burns, lesions and more. The nuts can be eaten raw and un-leeched in small quantities to treat diarrhea but I emphasize SMALL quantities. Excesive tannin intake can lead to kidney failure. The bark of the oak tree has the highest tannin and quercin content. Infusions of inner bark peelings have been used to treat tuberculosis and small pox. Oak wood is also good for making bow staves and baskets.

Once leeched the nuts are ready to eat and incredibly nutritious. They are high in protein and vitamins and minerals.  A handful of acorns has more nutritional value than  a pound of fresh hamburger. They are lower in fat than other nuts and low sugar so they are good for controlling blood sugar. Even though they are low in sugar they have a particularly sweet nutty taste so if they are to be used in any recipes calling for sugar the sugar amounts can be lowered slightly.

There is still some tannic taste which may not be palatable alone but they are delicious added to soups and stews. They can be ground down into a flour and used to make muffins and breads or almost anything else that calls for flour in the recipe. If they are going to be ground for flour then it is a good idea to dry the nuts a little befor grinding but they can be ground wet, especially if they are being used in a bread recipe and dried out after grinding. Acorn flour is very low gluten content so when making baked goods it should be mixed with wheat or corn flour.  If the recipe includes eggs this will also aid in the binding.

Im trying to find out where the oak trees are in the area in and around Seattle so if you know a location or come across one please dont hesitate to share and I wont hesitate to share a muffin. Fair trade?

Thanks for reading!

this post was shared on Idlewild Alaska

Featured at the Homestead Bloggers Network 


  1. I want a squirrel muffin. But I don't know where any oaks are up your way.

  2. I work in Lakewood WA (nearer to Tacoma) and there are literally dozens of Garry Oaks.

  3. Very interesting! We will have to give this a try. Great lesson for me and the kiddos! Thanks for sharing on Homestead Blog Hop.


    1. Thanks for reading! Hope we see you again :)