The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Brewer's yeast culture - infected?

patientman's picture

Brewer's yeast culture - infected?

I recently obtained a slug of Belgian (Chimay) brewer's yeast to use in baking.  I have a sourdough culture I started from scratch some time ago, and read up on starting a culture from brewer's yeast in a similar manner.   I did a pretty astute job of isolating the yeast from the trub in the slug I had, and sure enough, the starter took off about eight hours later.  I made my first batch of preferment using this starter a day later.  I let it ferment at room temperature for another 12 hrs, then put it in the fridge and made the dough the next day.

I skipped the yeast on the final dough, as I wanted to get all the Belgian yeast flavor I could.  After mixing the dough I let it sit and ferment at room temperature for a couple hours (as suggested by Peter Reinhart in Artisan Breads Every Day's San Francisco Sourdough recipe, which was the basic recipe I used, substituting my starter for the sourdough starter).  The dough then went in to the fridge where it remained for another 20 or so hours.  I pulled out a portion of the dough for one loaf, noting that it had not really risen in the fridge.  This ball of dough sat in a bowl on the counter and did nothing for the rest of the day.  When I woke up the following morning, about 18 hours after I took it out of the fridge, it had come to life.

So I made a boule, let it proof a couple more hours, and baked it (450 on a stone, steamed at the beginning).  It was about as I expected - denser than it should have been, and also extremely rubbery - which I'll attribute to overdevelopment of the gluten during the long fermentation.  All in all, not bad though - good interesting yeast flavor - actually tasted like Chimay a little.

While I was doing all this I took out the rest of the dough and started proofing.  It did the same thing and didn't really rise.  I didn't want to let it sit all night again so I baked about 10 hrs later.  Lackluster results.  The very wet dough did not rise up once formed, making it impossible to score.  Though it rose in the oven, since it was unscored it was cavernous inside.

So I started another set of preferments - one for pizza dough and one for bread.  I let them sit out and ferment at room temperature for about 18 hrs, hoping to get the yeast a little more active.  I came back to mix the final dough and found the preferment had acquired a very *intense* odor.  In the final dough (which again I let ferment at room temperature for 2 hrs for the bread, 4 for the pizza dough) I can only describe this smell as goat cheese-like.  I am excited to bake this bread, though as I sit here the bread dough is in my fridge, not having really risen after I mixed the dough yesterday.

What's this smell? Did my preferment get infected? I probably did not supply enough information along the way - any feedback about getting naturally fermented dough to rise right would be much appreciated.

Mini Oven's picture
Mini Oven

I have little experience using direct brewed brewers yeast for bread but I'm trying to grasp the rise power. 

First a few questions...  In the beginning of feeding the yeast, you said it took off 8 hours later.  When did it peak? and did you feed it at peak then 12 hours room temp (?°) and then a peaking starter into the fridge?  How did you feed it?  I'm thinking the yeast wasn't strong enough to raise dough, maybe ferment beer, but not concentrated enough for bread dough.  Maybe it should be used directly and not fed before using like a starter.

The description of the crumb sounds like too little yeast and then the "invasion" could be an invasion or the shifting of bacteria and yeasts from those that make beer.  Air plays a role here. Alcohol formation will deteriorate the gluten.  I think in order to save the dough, you should add some instant yeast and get it rising and baking, you may have to add some fresh flour and salt accordingly.

The cheese smell leads me to the conclusion that your Lacto beasties are working away, I think you are in the early stages of formulating a new starter only in bulk sizes.  Reduce and continue developing the starter.

If you want to pep up the yeast, it should be fed on the counter top in smaller amounts keeping only 1/2 cup of starter.   Discarding most of it and feeding at 12 hour intervals.  Important is to rid the starter of waste products and encourage those yeasts that produce in 12 hours to keep producing, once the yeasts can raise the dough, then the 12 hours can be reduced eventually to 8hrs to incourage faster yeasts. (The starter has to rise within that time period.) Discarding is important to keep the starter acid from going to low.  You want to maintain the proper pH to stimulate yeast growth.  Adding flour and water raises pH.  In also want to add enough flour to trap bubbles and still be soft enough to stir.

Some of our home brewers here might have some pointers for you.