Acorn beer beginnings

There are a lot of oak trees in this part of New Jersey, including some on our property. They drop acorns every Fall, but some years they drop a lot. Doesn't "acorn beer" sound appealing for Fall, like "nut brown ale?" I've semi-joked about it almost since I started homebrewing, in 1997. So this year (2015) the oak trees are dropping a lot of acorns. Remembering my comments, Lynn went and collected a little more than four pounds of acorns from the front yard, intending that I try them. How could I refuse? I love trying things, if there isn't too much work, sometimes even if there is.

I've googled "acorn beer," and found a bunch of hits on homebrew sites from people asking whether anyone had tried acorn beer. There was some discussion, but few mentions of results. The one I remember was from someone who tried making about a gallon of beer. He mentioned that it was quite bitter, and he'd try aging it to see if it smoothed out. I got the impression he did not soak the acorns to remove the tannin. So maybe there will be something worthwhile in this blog.

Acorns

I've also googled acorns, trying to find information on processing them. Korean cuisine seems to include the use of acorn flour, and you can get it on-line. I'm concerned about it being thoroughly processed, acorn starch, you might say, but I may be wrong. In any case, it's more aesthetically appealing to use acorns from my own yard.

I've found conflicting information on the nutritional content of acorns. Some say it's very close to that of barley, so good for beer. Others say it has a lot of fat, and so can go rancid. I suspect the different kinds of oaks produce acorns with different nutritional content.

Lynn tells me that the oak in the front yard is an Eastern White Oak. White oaks are supposed to have acorns with less tannin in them. And in fact, these acorns are pretty mild. We tried some raw, and they really don't make you pucker all that much, roughly the same as a walnut. By contrast, there is an oak in the back yard that Lynn says is a pin oak, a kind of red oak. Its acorns are very bitter. Good thing the white oak acorns are the less bitter ones, since they're quite a bit larger.

So lesson 1, white oak acorns may be better than others because of lower tannins.

By the way, they taste unusual but pleasant, kind of buttery, with a little sweetness in the aftertaste. Lynn collected some more, and shelled and soaked to remove tannins. She then oiled, roasted, and salted them to see if they worked as nuts for snacks. They don't quite. The taste is interesting, but they're a little hard, and the texture is a little odd.

Initial processing

Following some on-line sources, we baked them on low heat to kill any eggs or grubs in them. The source I followed said to bake them at 200°F for 30 minutes, so I did that, with the acorns spread one layer deep on three cookie sheets. I just turned the oven off after a half hour and let them cool overnight. The next morning Lynn took them out and put them on the kitchen counter. After a while she found a grub crawling away, so clearly they hadn't gotten hot enough. Lynn then baked them at 250°F for an hour. Although the meats were a fairly light tan when raw, after the time in the oven they are dark brown. They look like chocolate.

Then came the shelling. I used an ordinary nutcracker, the two-armed class-2 lever kind of thing, not the kind with the wooden figure that cracks the nut in its jaw. After an entire Eagles game I had worked through only half of the four plus pounds.

After another Eagles game plus fifteen minutes I had shelled them all.

There is a skin that sticks to some of the acorn meats, that's hard to get off, so I did not worry too much about it. It will mostly come off during soaking or mashing.

I stored the acorns in the big jar in the picture, flushed with CO₂, maybe being more cautious than necessary. After a few days I noticed that a few acorns had a little fuzz on them, I assume mold. Apparently they hadn't dried enough yet. So I baked them again for an hour or so (don't remember) at 200°F. I put them back in the big jar, which I had cleaned, sanitized, dried, and put in my chest freezer (~45°F). As soon as the acorns entered the jar, water started condensing inside it, so they were still out-gassing water. The next day I put them in the upper oven with the oven light on and the door cracked, as Lynn suggested, and left them for a day. No more condensation in the jar. I can't get to the beer for a month or so, so I flushed the jar with CO₂ again, and I'm storing them in the chest freezer. There are a little more than two pounds of acorns, now that they're shelled and dried.