Acorns to wort

Preparing the acorns for mashing

I don't know that soaking to remove tannin is necessary for these acorns, but I did it this first time just in case. I covered the dried acorns with cold (filtered) water and let them sit for a couple of hours. They soaked up some of the water, and the remainder turned a little cloudy and green. Surprising, given that the acorns are a chocolate brown.

After a couple of hours I drained the acorns and covered them again with fresh water, this time about twice as much as needed to cover. I was thinking if they just soak it all up, the tannin may be in the water but the water is inside the acorns, not out as desired. I let this go another couple of hours. I repeated this several times. One soaking was overnight, so longer than two hours, and another was a few hours while we were at church. They were soaking for more than 24 hours, all together.

In the last installment I mentioned a skin on the outside of the acorns that doesn't always come off easily. Some of it comes off during the drying, so you get flakes floating around, and the rest
seems to come off during the soaking. I haven't thought of an easy way to separate acorns from flakes. The acorns settle more quickly than the flakes in water if they're all stirred vigorously, but the flakes still settle fairly fast, so without a deep container it's not terribly effective. I removed quite a lot of the flakes by hand, while transferring from the sieve back into the jar in which I was soaking them.

During soaking, my acorns turned an unappetizing greenish-gray. When Lynn baked and soaked some for roasting, to see if they made good snack food, they came out "blonde" after soaking, and dark brown again after roasting. Hopefully the beer won't come out greenish-gray.

Some of the acorns after soaking. This was intended to show the odd greenish-gray color, but I was aware that camera-monitor systems don't reproduce color very well.

 I then ran them through the fine blade of a meat grinder. They are tender enough for this after the soaking.

Meat grinder, ground acorns, and acorns. Note the circa 1980 appliance color. The box says "Harvest Gold," but it leans toward avocado. No doubt it has changed in those 35 years.

Recipe and mash

I did an adjunct mash with the acorns, the day before the main mash. Following Mosher's description in Radical Brewing, I mashed the ground acorns and about half as much six-row malt together. I used rests at about 100, 120, and 155 degrees. Mosher's description doesn't include the rest at 100 degrees, but I was hoping this rest, which is supposed to help degrade glucans or gums, would help break down the acorns. After boiling it I let it cool overnight. In the morning I heated it to about boiling and mixed it into the main mash just after doughing in.

Adjunct mash, after sitting overnight. Thankfully the color is no longer greenish-gray.

For the recipe, I was torn between making a beer that might come out too boring, and one in which other flavors are confused with acorn flavors. An acorn IPA with Brett is out for this first try, at least. A recipe of acorns, pilsner malt, and a small amount of hops leans a little too close to acorn tea. So, I'm aiming at a brown ale (nut-brown, in this case) that's not too roasty but would probably be okay without the acorns. The recipe is

Adjunct mash

1 lb six-row malt
2 lbs acorns (shelled and dried, before soaking)

Main mash

8 lbs pale ale malt
1/2 lb 60L crystal malt
1/2 lb victory malt
1/4 lb chocolate malt

Hops

3/4 oz Horizon pellets, 10.1% AA, 60 mins
1/2 oz Willamette pellets, 5.2 % AA, 20 mins

Yeast

Wyeast American Ale 2 (1272).

I intended this to give an OG of 1.058, and 35 IBUs.

The home brewery (in the garage). It's mostly pretty simple. This really has nothing to do with acorn beer, I'm just throwing it in.

I used a no-sparge procedure. I was aiming at 6.5 gallons of runoff, but got 7.5. Apparently the acorns don't hold a lot of water, but that doesn't explain it all. Probably I added more water to the mash than intended. The runoff had a gravity of about 1.041, which, with the volume, is less extract than I hoped to get. I'm guessing it's because the acorns don't break down much in the mash. The adjunct mash still had lots of fairly hard bits in it.

I boiled the wort for 90 minutes. At the end of the boil and cooling, the actual OG was 1.053, and the volume was a little less than 6 gallons, 5.5 in the fermenter. The wort is a dark brown, dark enough to be a brown porter, I'm pretty sure. Some of that seems to be from the acorns, since the malt bill by itself shouldn't give wort that dark. There is evident acorn flavor in it, not intense but not too subtle, either. It may stand out more after fermentation.

Fermentation didn't start for more than 24 hours. I oxygenated well, so either I should have kept it warmer, or I should have made a starter, or both. (Oxygenation worries me, in a case like this. I'd think there's more time for the oxygen to do bad things before the yeast eats it.) The rest of the fermentation, secondary fermentation, and kegging will be completely standard, so I won't write about that, unless something weird happens.