People have been using bread yeast since time immemoria, long before there were different, cleaner tasting, strains for brewing. In fact if you look at the first beer recipe, the "Hymn to Ninkasi" in the Tales of Gilgamesh,you will find that a special bread was baked, and that bread was added to the cooling mash...it was the yeast from this "Bappir" bread that induced fermentation.
The Maltose falcons and Anchor brewing worked on recreating the recipe several years ago, here's a pic of what they think the bappir looked like.
It's also been used my mead makers as well...
Here's the basic brewing video on using bread yeast. http://www.basicbrewing.com/index.ph...nd-bread-yeast
you'll find the results surprising. They pretty much shoot down the off flavor idea....
Also check out Michael Tonsmier the Mad fermentationalist's experiments with different yeasts.
September 20, 2007 - Offbeat Yeast Part One
Michael Tonsmeire, the Mad Fermentationist from Washington D.C., shares some of his beers made with other-than-normal yeast. In this episode: Kvass, Flanders Red, and a Strong, Dark Belgian.http://media.libsyn.com/media/basicb...fbeatyeast.mp3
September 27, 2007 - Offbeat Yeast Part Two
We continue our tasting with Michael Tonsmeire, the Mad Fermentationist from Washington D.C. This week, all the beers are fermented with Brettanomyces.http://media.libsyn.com/media/basicb...beatyeast2.mp3
In other words, it's been used forever, and is still being used by brewers and mead makers, especially those without access to beer yeasts (THere was a guy on here this winter from Bulgaria who can't get any brewing ingredients). And also it is used currently by some people on the Grocery and produce experiment thread.
It won't kill you, it may or may not produce negative flavors in the beer (most of this is lore/conjecture passed on by people who haven't even actually tried it.)
Certain beers may even benefit from the "bready" taste that may be produced, think Kvass or a dark beer with a lot of roasty and biscuity malts in it.
Plus Experimentation is fun.