Yeast from home brew

In fact, that is how people in some areas of the world used to get their yeast, rather than keeping a sourdough starter. The commercially sold "bread" yeast you'd find in grocery stores is actually "brewers" yeast - the same yeast you use for making your home brew. It is not a wild yeast. It has been cultivated to give quick and consistent results. If you want a wild yeast sourdough starter, you don't need to start with anything but flour and water. The wild yeasts and lactobacilli are already present on the grain. But, if you want to, there's nothing wrong with starting your culture from your home brew. It is simply redundant. If you want sourdough, it works without the addition of commercial yeast, and if you want brew yeast, you don't need a sourdough starter, because you presumably already have the yeast for making home brew.

If you do decide to make a starter culture from the yeasty brew, simply add some of the brew to about the same amount of flour, or enough to make a pancake batter consistency. Wait until it bubbles up to its highest point, and discard some of that, replacing with fresh flour and plain, clean water. For more detailed instructions, look up starter maintenance on this site. Consider your starter to be "mature" and "established" pretty much the first time you mix it up, or maybe the second, since you are using commercial yeast.

So, basically, you can use it(after each brew session), but you cannot perpetuate that strain of yeast.

This question pops up periodically here. Do a search for "brewers yeast" and you will probably come up with a few threads where this is discussed, for however long.

I get the feeling most end up not bothering.

This conversation is inspiring me to ask either the neighbor across the street or the colleague in the office, both of whom home brew, for a bit of beer for a second starter. Would be fun to see what happens and to make a bread the way it was first made.

Most beer yeasts were derived, and sustained for their efficacy to ferment malted grains, predominantly barley in the USA and Europe, but other grains are also used. Furthermore, at least half of the yeast strains used to brew modern beers are chosen, in part, for the flavors they impart to the beer. For example, one yeast used for making wheat beers imparts a strong banana-like flavor to the finished beer. Some beer yeasts may impart unwanted flavors to bread.

Baker's yeast, on the other hand, while of the same family species as brewers' yeast, Saccharomyces cerevisiae,  its strains appear to be chosen to impart little flavor to doughs, and primarily provide rapid rise-times. Lager yeast, saccharomcyes pastorianus, is a different specie entirely, and probably not well suited to bread baking.

Lastly, mature, stable sourdough cultures are frequently "tight" partnerships between specific bacteria strains and specific yeast strains: apparently symbiotic groupings. With a few exceptions (e.g.,Belgian lambic beers, malo-lactic conversion in wine) there aren't many alcoholic beverages that rely on both yeast and bacteria for their production.

I'm a firm believer that sourdoughs starters created from simply flour and water (or acidified water (see "The Pinapple Juice solution" posting) are a reliable source for us amateur bakers.

If you decide to try brewer's yeast I suggest you use yeast collected in the foam (krausen) topping the primary fermentation of ale, or yeast gathered from the fallout after secondary fermentation has recently completed. The yeast that collects in the bottom of a primary fermenting container is mostly dead cells.

Happy baking,

David G

most bread made in the olden days, before commercial yeast became available in the 1870's, was made with  sourdoiugh.  Modern food anthropologists, (who knew there were such folks) now know that almost all bread from the time of Egypt until commercial yeast availability was made from either wine or beer barm where bakers scooped off the yeasty foam to us ti raise their bread.   This supposedly accounts why bakeries  were located next to breweries.  Sourdough baking is actually one of the newest ways to make bread and considered cutting edge.  People who were traveling long distances, like the pioneers,  without bread or breweries available along the way or those out in the boonies or hinterlands for a long time like the Gold Rush 49'ers were the ones who used SD to raise their bread.

When I go to the brew store I am amazed at how many different strains of brewer's yeast are available to make different beers but none of them is the commercial bakers yeast we know today. Commercial breweries protect their yeast strains religiously and it is hard to get some foam from them but some some craft breweries will let you take some on occasion.

I have made all kinds of bread using barm over the years and it works well enough -made good bread,  but there is no sour flavor that SD brings and that I prefer so I don't really bake with it anymore.  It is a fun experiment with barm though say to use the yeast for a dark stout  beer to make a dark stout beer bread. 

I did make a hops SD starter and a hops YW starter not long ago.  The SD starter eventually lost all of its hops bitter flavor and you could not taste it the bread and the YW starter was just bitter all the time and we didn't like the bread made with it.

i say do some experimenting and see how it works for you.

Happy Barm baking