No Yeast at the Store? No Problem. It’s Everywhere in Your Home

sourdough starters are not the same thing as what people are used to with instant, active dry, or even fresh yeast. Sourdough starter requires reasonably good timing, while instant/active dry/fresh yeast do not.

Unless you are a professional bakery, keeping sourdough alive for 60 years, is a waste of time. This is because the organism involved is constantly impacted by the current environment, wild & indigenous yeasts, bacterias, each and every time there is interaction with the environment. This interaction is not only the air, but the flour, utensils, and people touching the starter.

There is a possibility that a specific strain of bacteria and fungus survived for 60 or even longer, but it is unlikely for a home baker. That said, taking sourdough starter, drying it, and keeping it in dry place could prolong the particular combination.