As I have previously mentioned, we have a number of oak trees, but this one is the oldest. We estimate it to be between 250-300 years old and are concerned that it is reaching the end of its life. The average lifespan of a white oak is around 300 years and we have noticed that it isn’t looking as healthy as the other oak trees we have.
The way we calculated the age of the tree was to measure around the trunk at 54 inches above the ground. You then calculate the diameter (circumference divided by pi). Multiply the oak’s diameter by the growth factor to find the age. The growth factor for white oak is 5. This is the growth factor for forest-grown trees, which grow thinner than street trees. Street trees tend to be more stressed and grow slower and weaker.
We have a weird kind of relationship to this tree. It stands at the end of the drive and overlooks the cottage. Knowing how many years it has stood there seems to give it a certain presence. I can see why cultures have held the oak tree in high esteem. Somehow its presence seems to command a certain kind of respect and we will often greet “Mr Oak” as we pass by.
It is strange how we feel the need to protect it. It seems to have done quite well without us for the last couple of hundred years and we don’t want to be responsible for changing that. However, as previously mentioned, we eventually need to so something to decrease the slope on our driveway. One option is to move the driveway over, making it longer and the incline less steep. The easiest option would be to take it right where Mr Oak is standing and we feel we can’t possibly do that!
We were seriously thinking we will take the driveway to the other side of the oak tree, but there is a risk that in making the new driveway we will disturb the roots of the tree. The effects of root disturbance can be quite devastating and it can take between five and ten years for the results to become fully visible. Ninety percent of the root system is in the first 12-18 inches of soil and extend radially from the trunk between one and two times the height of the tree. The closer to the tree the construction occurs, the more destructive it is, so we have a feeling that sorting out our driveway issues will be issuing a death warrant to Mr Oak, whatever option we take.
Given the age of the tree and the fact that it isn’t looking as healthy as the other younger oak trees, it may be that its days are numbered anyway. We probably need some expert advice, but it will be a hard decision to make if we are advised to take it down sooner rather than later. Some people have suggested we should consider harvesting its valuable wood before it is too late. It seems sacrilege to cut it down just for its wood – but maybe we are being too fanciful in our attachment to Mr Oak. We also protest that he provides shelter for the porcupine and food for the animals, but there are other oaks that do that and if we are honest our real motivation is more whimsical than practical!
Apparently white oak acorns are edible for humans too and were eaten during the Palaeolithic, Mesolithic, Neolithic, Copper age, Bronze age and Iron age, as well as by many Aboriginal peoples. Today the biggest market for acorns is in Asian and one can buy acorn flour and noodles there. The kernel of the acorn is dried and ground into flour. An alternative to making flour is to roast them in hot coals and eat them as a snack. I don’t think we will ever find more than enough for a small snack, after the porcupine, white-tailed deer, squirrels, chipmunks, wild turkeys, woodpeckers, jays, bears, foxes, rabbits, raccoons, mice and voles have had their fill!
If we were serious about eating acorns we would need to process them first. There are two methods to leach out the tannic acid, which causes nausea and digestive issues. The quicker method is to shell the acorns and then soak them in hot water for about three hours. You may need to repeat soaking them until they are palatable. Once the acorns are properly leached they can then be dried and ground into flour or roasted. To roast them it takes about 15-20 minutes at 375 degrees and you can tell when they are done as the colour changes a little.
Acorn flour is rather crumbly, so it works best in recipes where the dough sticks together well – such as peanut butter cookies. To preserve the starch, which is destroyed by the boiling process, and make the flour more able to stick to itself, cold leaching is a better option. It can take a few days or even more than a week to do it this way, but the result is a better tasting and an easier flour to work with.
Another tip about processing is that you need to make sure the skins are removed from the acorn. They are very tannic. If you freeze the acorns first, the skin comes off much easier when you crack them. As you crack the nuts, put them into water to prevent them from oxidizing. Any papery skins should come off once they have soaked for a while.
For the cold leaching method; once the acorns have soaked and all the skins have been removed, put them in a food processor. Fill about 1/3 and then add water to the half full mark. Blend until you get what looks like coffee milkshake. Put in a large glass jar in the fridge and add 50% water. Every day, strain through cheesecloth. Add water, shake and put back in the fridge. You know the flour is ready when it tastes bland and all the bitterness has gone. Spread the flour on a baking sheet to dry it or use a dehydrator. You will end up with coarse flour, so the last step is to use a grinder to turn it into powdery flour.
This seems like a lot of work, but I am assured that the flavour is worth it. It is much like the flavour of chestnut flour; nutty and sweet. Acorns are very nutritional too. They contain starch, oil and protein, have a high level of antioxidants and a low glycemic and insulin indices. A 100g serving gives 37% of daily value for fat, 14% carbohydrate and 12% protein. It also contains 25% of daily value for vitamin B6, 67% magnanese and 16% magnesium, along with many other vitamins and minerals.
Whilst there is no caffeine in an acorn, you can make a coffee substitute from acorns. You roast them for about 30 minutes at 400 degrees. When the pieces are dark brown and smell roasted, they are done. Don’t let them burn! Steep one tablespoon for 5-10 minutes to make your acorn beverage.
You wouldn’t want to drink the potion that is left after leaching the acorns in hot water because of the tannic acid, but it does have uses. It can be used to tan a hide and it also has medicinal uses. Swishing your mouth out and holding the liquid in your mouth as long as you can helps toothache – but don’t swallow it. A cotton ball soaked in the potion helps ingrown nails and other inflamed skin ailments. A tablespoon in hot water can help with diarrhoea, but blackberry roots is a better source of tannic acid than acorns for this use.
Whole acorns dried in the shell may last for several years, so maybe I can start collecting just a few each year. Who knows how many years it will take before I have enough for one batch of cookies – but it would be fun to give it a try!