Baking bread from a 4,500-year-old yeast from Ancient Egyptian pottery

Post by gingabriska » Tue, Aug 06, 2019, 4:35 PM UTC

abeppu wrote: post #2

Even if some of the yeast is from ancient strains, I wonder if it's really feasible to get a mix that's representative of what was in those containers 4,500 years ago. Shouldn't the population be changed by the selective pressure of being starved and dormant for that long (i.e. the ones that can be revived might be a small minority)? Or for yeast, is chilling for millennia no big deal?

Post by rleigh » Tue, Aug 06, 2019, 6:17 PM UTC

sgt101 wrote: post #8

MidnightRamen wrote: post #7

Earlier quoted context omitted.

The issue with old strains is similar to the whole concept of homeopathy. Sure, the original strain might be 4000 years old, but keeping a sourdough starter usable means keeping it exposed to air where it gathers fresh bacteria, eventually leading to the starter being statistically significant only to the bacteria of the locale, not the source of the starter.

I'm confused - yeasts are not bacteria?

Post by antisemiotic » Tue, Aug 06, 2019, 7:23 PM UTC

MidnightRamen wrote: post #7

abeppu wrote: post #2

Even if some of the yeast is from ancient strains, I wonder if it's really feasible to get a mix that's representative of what was in those containers 4,500 years ago. Shouldn't the population be changed by the selective pressure of being starved and dormant for that long (i.e. the ones that can be revived might be a small minority)? Or for yeast, is chilling for millennia no big deal?

The issue with old strains is similar to the whole concept of homeopathy. Sure, the original strain might be 4000 years old, but keeping a sourdough starter usable means keeping it exposed to air where it gathers fresh bacteria, eventually leading to the starter being statistically significant only to the bacteria of the locale, not the source of the starter.

Post by NeedMoreTea » Tue, Aug 06, 2019, 9:40 PM UTC

girzel wrote: post #16

antisemiotic wrote: post #15

Earlier quoted context omitted.

If the yeast in your sourdough have been replaced by bacteria gathered from the air, then I think you should throw it away ASAP.

Every locale has its own indigenous yeast variants. Unless you go to ridiculous lengths to isolate your starter from the environment (which some people do, including sterilizing the flour used to feed the starter), it's going to eventually be taken over by local yeast. Which, IMHO, is a fine thing! Bake where you are.