life in the so called space age

Monday, May 3, 2010

Banana beer

So I started the experimental banana brew last night that I've been mulling over for some time now. I based it off of a vague, traditional Ugandan recipe, but made some significant changes. Most notably, rather than using only banana juice in the wort, I used puree'd bananas. 2 reasons for this.. First, juice extraction seems time and yeild restrictive. While I've read that there are scientific methods to yeild up to 75% juice, I'm certain I can't come near that. Secondly, the journal articles I've found regarding banana starch seem to indicate that it's kind of "self worting", ie: the ß-amylase breaks down the starches into water soluble sugar chains. This also means that it has high diastatic power, and can break down other starches, in my case, millet flour.

The most questionable aspect of this experiment is the amount of bananas I used. I was shooting for around 1/3 the total volume of the brew, (a 5 gallon carboy) which came out to be 5 bunches. This 1/3 figure was derived from the original recipe, but the 1/3 was the amount of banana _juice_. I expected the whole bananas to be less potent, but to also have a higher fermentable sugar output. since I have neither a metric or means for measuring these yet, it just called it even for the sake of experimentation.

After adding the banana slurry, I added sterilized water with millet flour mixed in. (note1: don't add flour to boiling water note2: the only place in town I could find millet flour was natures pharm) I then added a dry ale yeast starter that I had pitched about an hour earlier. The reason I went with this yeast was because I had it on hand, no other reason. Traditionally, the natural banana bacterias would be the sole fermentation agents, and may be something that I try later on, but for now I wanted to try and keep it as clean as possible. This included a dilemma as to whether I should heat the wort to try and kill the bacteria. (as I did with the last batch of cider) After talking to Belinda and Nancy about it briefly, it seemed like the heat might interfere with the natural starch->sugar process, and if my pitched yeast was strong enough, it would probably overwhelm the natural stuff anyhow.

There was little activity last night, but when I got up this morning I found a decent amount of off-gassing, as well as an airlock full of banana sludge. The brew had settled out and about half the carboy was traub. This is my main reason for doubting the amount of bananas added, but I'm hoping that the solids will continue to break down as the yeast works. To this end, I'm planning on agitating it daily, and I'm guessing I'll be changing the airlock daily as well. My only concern other than the solids is the mystery esters that may be produced.. but then again, if I knew what was going to happen, it wouldn't be much of an experiment.

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