All purpose flour and wild yeast don't mix (or how AP just about killed my starter)

For years I have used whole grain flour for everything. I have been able to make new starter in less than a week with just flour and water... no extra tricks. A month ago my wife got me a bag of all purpose flour (not even UB!). I have been using it for non-important things. I was using it to feed my starter... I got away with that once (50% whole grain still left) then the next time I got bricks instead of bread because the starter which I normally feed and leave for 6 hours, was still not doing much 24 hours later.... I should have just postponed the bread. Anyway, I have recovered it by tossing half and adding whole grain back in a few times. The AP was Robin Hood brand BTW.

I was surprised as I thought the yeast/bacteria would grab any old starchy stuff, but they seem to be quite picky. Anyway, the AP is all gone (big sigh of relief) and I can get back to my normal whole grain breads

That is a really interesting observations. Most likely your yeast are used to a very nutrient rich medium whole wheat,
whereas the processed flour is only carbs and not other nutrient in it. Most likely you would have to create a new strain of yeast that loves process flour
and it would take a few generation to go from 25% process flour to 50% to 75% to 100% process white flour, but it is possible.

S Bengi wrote:That is a really interesting observations. Most likely your yeast are used to a very nutrient rich medium whole wheat,
whereas the processed flour is only carbs and not other nutrient in it. Most likely you would have to create a new strain of yeast that loves process flour
and it would take a few generation to go from 25% process flour to 50% to 75% to 100% process white flour, but it is possible.

I think there may be more to it than that. Aside from oxidizing it to bleach it, there may be added preservatives (AKA poison). I have never had problems making new starter which I have normally done once a year. However, I have seen posts on this and other forums of people who have had a hard time getting them going... even using pure water, adding pineapple juice and other tricks. I am wondering if those people actually had a flour problem. That is the main reason I posted my experience. So that if someone is having trouble growing wild yeast, they will also look at what flour they are using. I have used UB (white unbleached), whole wheat (cheap stuff which is ub with bran thrown at it) and whole grain (includes everything in the grain) both the cheap Rogers stuff as well as stone ground varieties (my favourite when I can get it). I have also used rye and even ground barley or Channa (ground pea). This is the first time I have had any problem. I have been using wild yeast for about 6 years now on a weekly basis and experienced various failures in bread making, but this is the first time I have had my starter fail.

I think it is important to share failures as much as success.

The actual processed % would be 50% the first gen and 75% the second (when it failed). The 50% was ok, though it was a bit slower (I thought it may have been that the room was cool, but putting the culture in a warm place did not help).