The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Ruin with "fast rise" yeast?

rockaday's picture

Ruin with "fast rise" yeast?

About a week ago I was adding some starter to a dough that had some grocery store "fast rise" yeast in it. I don't remember exactly what I did, but something like wipe or stir the spoon in the dough and the return the spoon to the starter, and then immediately I was like "Oh maybe I shouldn't have done that."

Would the introduction of "fast rise" grocery store yeast to a sourdough starter act as an invasive species that takes over where it isn't wanted and ruin the starter?

My starter seems fine since then... or maybe it's tooo fine -- I've noted that it's rising well. But I'm not experienced enough with starters to be sure whether something's amiss. It was quite excited today when I fed it with WW flour (I usually use AP).

idaveindy's picture

WW ferments a lot quicker than AP.  That could explain your starter's rapid growth.

It's likely the commercial yeast will die off in the acidic environment of the starter.  they aren't designed for it.  

It may take a few days.

rockaday's picture

Thanks for your reply. I'll leave it in a warmer spot tonight, about 79 F, to drop the PH a bit in case there's some in there.

Mini Oven's picture
Mini Oven

putting the starter, provided it has fermented enough to increase the bacteria, into the refrigerator will also drop the pH and increase acid being produced by the bacteria.  Bacteria are at their lowest level right after the starter is fed.  Yeast increase and about the time of a first peak, bacteria start to rev up increasing their population.  Chilling after the starter starts to fall will send messages to the bacteria and they switch to survival mode putting out more acids to survive the situation until temps become more ideal.