Saturday, December 3, 2011

Potato & Sweet Potato Beer

Last week's brewing day ended up being incredibly long due to the fact that I tried to brew three beers in one day. My main 5-gallon batch was a Robust Porter, using 9# Weyermann Pilsner, 1# Caramunich I, 1# dehusked Carafa I, 0.75# Weyermann Light Munich, and 0.25# Weyermann Roasted Barley. I always like to go strong on the dark malts, which is actually a good thing given that my water pH is something like 7.6. That brew was uneventful, and the smell coming through the airlock was heavenly. 2 oz. of Glacier for bittering and 1 oz. Hersbrucker for flavoring led to a really nice minty, hoppy smell coming through the vodka in the airlock.

What really took a long time were the two one-gallon test batches I made, of potato beer and sweet potato beer. For the potato beer I used a little over two pounds of white potatoes, which ended up being around two pounds after peeling. I started to grate them but decided just to chop them up and boil them. Once they were nice and soft I put them through a SpƤtzle-Schwob and let them cool. Then I added 1.5# Weyermann Pilsner and enough water to get to around 6-8 quarts. I applied direct heat to get them to saccharification temperature and let them mash for around two hours to ensure that all the starch was converted.

Then I strained the wort through sieves into my brew kettle and boiled for about 45 minutes with 1/8 oz. of Hersbrucker until I got down to around 1 gallon of wort. My OG was 1.055, so I ended up with a contribution of around 13ppg from the potatoes, higher than the 8ppg I had read from other sources, so assuming an normal attenuation of 75% I should end up with around a 5.5% ABV beer.

I tried the same thing with the sweet potatoes, albeit with 1.5# Weyermann Vienna, and in my normal mash tun with the bazooka tube. Big mistake, that thing clogged like crazy. Not a bit of liquid made it out. So I had to improvise. But everything worked out well. As you can see in the photos, the potato beer is on the left, the sweet potato beer is on the right.

There was quite a bit of grainy material in the beer, and as the second photo shows, much of it ended up settling to the bottom.

So out of a gallon of wort I'll be lucky to get half a gallon of beer. Not really worth the effort, but we'll see how it tastes. I'll probably wait a few weeks to bottle, so that maybe sometime early next year it should be ready to drink.

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