Spontaneous Fermentation

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Apr 6, 2012
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My last batch of beer I decided to collect a couple extra gallons off my sparge of a high gravity beer and boil it down for starter wort. I boiled it down to a gallon of 1.030 unhopped wort and poured it into some sanitized canning jars. The thinking was that the heat from the wort would sterilize the jars and the lids would seal as they cooled. I hit the jars with a thermometer and it read 200 degrees on the lid and glass after I capped it. A half hour or so later, I heard the lids pop and seal as they cooled. Things were looking good. 5 days later I heard some hissing and a nice krausen had formed in the small headspace of a couple jars

The lesson, proper canning procedures are necessary if you're attempting to harvest extra wort.... shortcuts in canning are not the solution. The other lesson, either yeast are very resilient or I have some wild yeast floating around to experiment with spontaneous fermentation.