In preparation, I did teh Googlez for a while to see the current state of the art, then made an interesting realization: there are two distinct products which could be considered sorghum-based beer. One is a cloudy, sour product of African origin, similar to a lambic or other sour beer fermented with wild yeasts or bacteria, but based on malted millet (the seed of sorghum) or cooked millet catalyzed by salivary amylase.
Hmm. This, apparently is what is meant by a gluten-free beer; it is brewed entirely from millet with no barley component whatsoever. Sounds scrumptious, but that’s not what I was after.
It turns out what I am looking for is not exactly a 'sorghum beer.' It's more a 'beer with sorghum in it.' I plan a simple ale, lightly hopped, with a small portion of light or amber malt (say, 2 to 3 pounds) augmented with sorghum molasses.
A traditional favorite of the deep south, sorghum molasses is made by crushing sorghum stalks and boiling down the extracted juice in open pans, as you would boil maple sap into maple syrup. More flavorful than cane syrup, less intense than molasses.
Now all I need to do is figure out how much a given amount of sorghum molasses will contribute to the specific gravity. I don’t want to have another debacle where I end up with an absurdly low starting gravity by underestimating the contribution of an adjunct—as so often happens with honey, et al.
I have a little over two quarts of sorghum to play with. For a five gallon batch, that could be as much as 1:10, so I suppose I could test its contribution by dissolving ¼ cup of sorghum in 2-½ cups of water and measuring the gravity. That sounds all science-y.
I like science-y stuff. Stay tuned; I may brew in the morning. If that's the case, look for a test-drive around...Thanksgiving!
Update: Okay, science-y types: It turns out that one part sorghum in 10 parts water yields approximately 1.050; therefore, when I brew, I plan to start with 3 pounds of light/amber malt extract, then add one full quart of sorghum (1:20) and take a gravity reading. That should put me in the ballpark for a decent session ale. Updates as they happen.
Update #2: In Which Your Faithful Brew-Ogger discovers he is, in fact, making green beer: As I read the label of the sorghum, I discover it is:
"MADE THE OLD FASHION WAY WITH HORSE POWERED MILL AND WOOD FURNACE"
and is made (THE OLD FASHION WAY) just one state away. So how local and renewable can you get? In any case, so far we've got a pound of crystal malt, two pounds of NB golden malt, gypsum, and—hold onto your OLD FASHION hats—8-½ pounds of sorghum. Yeah, I went all in on the sorghum, based on some more intermediate science-y stuff I did once the brewing was underway. Look for a fairly modest hopping schedule, but I'm very optimistic and enthusiastic about how this stuff will turn out.
Update #3: I did the usual trick of adding gelatine to fine the beer, but it seemed to do absolutely nothing whatsoever. As a result, we bottled "SeptemberFest" as a murky brown ale with an odd yellowish cast. Perhaps it will bottle clear, or simply remain cloudy. Don't recall seeing this effect in any other brews. Oh, and a preliminary taste test suggests two things: One, it has a similar taste profile to the ale I brewed using maple syrup; two, to me it has a pronounced caramel (like Kraft Caramels) flavor, though Mary doesn't notice this. Now we wait.