The yeast wranglers of Kortenaken, Belgium, got better at it over the years.
In the beginning, homebrewers Tom and Wim Jacobs would leave out wort samples in small Erlenmeyer flasks. Typically, they would add local berries or other produce, to see what they could harvest from nature’s own tiny fermentations. Out of 10 samples, maybe one or two would turn out pleasant enough to step up and try in a brew. As they developed experience and a sense for what works, about half of those indigenous yeast samples would succeed.
