In Issue 7 (June/July 2015) of _Craft Beer & Brewing Magazine®, _my article, “Spontaneity: Prospecting for Bugs,” outlines how to use a homemade coolship or horny tank to ferment beer with your own hyperlocal blend of microflora. Included in the article is the image above of a pan full of wort, which I left outside for several days—enrobed in cheesecloth and enduring alternating bouts of wind, drizzle, and sunshine—before the photographer came over to snap the photo.
Almost two months have elapsed since that image was taken, and I’m happy to report that my mystery blend of microbes is doing well. After my DIY coolship had spent about a week outside, minute colonies of mold had begun to grow on the surface of the wort. After skimming these off, I poured the remaining liquid into a Mason jar, which I brought inside my house and placed on the kitchen counter for daily observation.
I continued to skim mold from the surface every couple of days, but by the end of the first week in the jar (so, two weeks total), visible signs of fermentation had become apparent. Small bubbles rose to the surface, the liquid became opaque, and a thin Kräusen formed on the surface. Once fermentation got going, the environment had become inhospitable to mold, so skimming became no longer necessary.