Spontaneous Fermentation

Written by Damon on July 24, 2010

I haven’t posted much lately partly for lack of inspiration and partly because blogging is a big part of my day job now, but this I had to share.

As an experiment, I drew off a portion of pale ale wort last weekend and put it outside over night to see if I could get spontaneous fermentation.

It being the middle of summer and a little on the warm side I fully expect whatever I get to be undrinkable, but I might try mixing it. Spontaneous fermentation is normally started when it is 16° C outside because that favors yeast over other organisms enough to make the final product drinkable.

The normal way to start spontaneous fermentation is to cool the wort in a coolship, a large metal tray about a foot deep, in the open air and let the organisms naturally drop in.

Spontaneous Fermentation

Click the image for the ridiculously large sized version.

I used cooled wort because I was making another beer and couldn’t be bothered to measure hot wort. The side-effect is that maybe this little experiment will be drinkable despite it being in the 20°-26° range.

I left the wort out on a porch overnight until mid-day. Fermentation started about three days later. After about a week, the beer doesn’t look like a normal fermentation. I don’t know if that’s good or bad, but if you know what forms large bubbles on top of the wort that seem to last for days at a time feel free to inform me.

The aroma is intriguing. It smells very much of red currant with a hint of green apple and the aroma is really strong for something still in the early stages of fermentation. I haven’t tasted it yet. I figure it will be fall before it is close to ready and spring before it is stable.

Posted Under: Home Brewing

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