It’s acorn season here in the Kootenays, and this year the oak trees on the East Shore of Kootenay Lake are absolutely filled with lovely little capped nuts. After some guidance from Hunter, Angler, Gardener, Cook, and a trip out to the local oaks to gather a small bucket full of the cute green fellas, I set them out to dry on a cookie sheet for a few weeks on the mantel above our wood stove. After they had turned a beautiful brown, they were shelled (I used pliers, which worked well).
Acorns have tannin in them. In fact, the word tannin comes from the Old German word (tanna) for acorn and oak tree. How much tannin, and, therefore, how bitter they are, depends largely on the variety of oak that they come from. The ones in my neighbourhood are, after close inspection and a look in our tree guide, a type of English Oak, which seems to have a moderate but quite noticeable amount of the bitter substance. To remove this I used a boiling method; putting the acorns in water and bringing the pot to a boil and then draining and repeating the process until the nuts were mild in flavour. I did this five times, which took about 45 minutes.
After the tannin had largely been removed, the acorns were laid out on a cookie sheet and roasted in the oven at 250 degrees for about an hour (they were checked every 15 minutes or so). This first batch ended up quite dark, no doubt due to a little too much time in the oven (they felt a bit soft still, when hot, but then firmed up after cooling, exactly like almonds do when toasted).
The nuts can be used in savoury meals (like chestnuts) and can be ground into flour, as well.