SC - Addendum on Rice Pudding

[Decker, Terry D.]

Sourdough is actually a relationship between yeast and lactobacilli with the
yeast providing the fermentation and the lactobacilli providing the
sourness.  The right combination makes for a good sourdough.  The wrong
combination a mediocre sourdough.

Sourdough yeasts tend to be very localized and are usually the yeast best
able to use the local grains and withstand the acid environment of the
starter.  Such a yeast is very often one of the Candida, because they tend
to do well in acidic environments. Every sourdough changes as you feed it,
but the original yeasts tend to be the winners in the environmental
sweepstakes, because they have the advantage of numbers in the starter.

Since we still make sourdough starters from wild yeast, the wide variety is
still there.  If we limited our starters to scrapings from the best
starters, we would have a handful of basic yeasts.  This is what has
happened in brewing and vintining to produce the optimal yeasts for making
the best tasting beverages.  And if you consider that variants of S.
cerivisae are the only commercial bread yeasts available, it is what has
happened in commercial baking.

There is no way to tell if all period ales were made with S. cerivisae.
Scientific consideration of yeast and the serious examination of the
organisms begins in 1872 with Pasteur's paper on fermentation.  However, if
we consider that human husbandry of yeast for brewing and baking is over
5000 years old, the probabilities are the selection process was well along
by the Middle Ages and that S. cerivisae represents the common strain from
that time.

Bear 

> However, I need to get a brewing book and look into the 
> question, since
> sourdough yeasts can be any one of hundreds... and I wonder 
> how we know
> that all the period ales used that stain of yeast.
> 
> -- 
> Jadwiga Zajaczkowa, mka Jennifer Heise