Originally posted by MarkusTay
I make bread in the kitchen, and I brew in my attic, so there is a whole floor in my house between the two. I don\'t think I get any contamination, and I don\'t think that would effect it regardless. Sourdough bread is actually made with \'soured\' beer
First of all, sourdough is not made from beer. It is made from flour, water and yeast.
Take flour, add water and let it sit on the shelf for a couple of weeks adding flour and water daily. One day it will suddenly inflate like a balloon and you\'re good to go.
I know because I have done this. Some people start with a \"starter\" that in some cases has been going for generations. You have to have the right yeast in your environment, which is why San Francisco is known for Sourdough bread and Florida is not. Different yeasts yield different tastes.
Now, notice I never said add yeast. That\'s because it\'s in the air. You let it grow slowly by feeding the starter until you get a critical mass (and you have to keep feeding the starter afterward too, like any living thing it needs new food).
Here\'s the thing: unless your first and second floors are air tight from each other, your yeast will travel through the air and do battle with the other yeast. The other thing of course is there has to be enough yeast in the air. Guess what; the more you bake/brew, the more yeast escapes into your air. So while you could do both for a while, if you do both frequently, the yeast will eventually reach that point where there\'s enough to compete for resources and your beer yeast will win.
So, you could have gotten bad yeast, but you may also have finally brewed enough beer to create a powerful yeast army.
@marineboy
In days of yore, beer making was a carefully guarded secret and most people did not bake. We have time now to generalize and do lots of things, but in the past people tended to be more specialized. Also, baking is necessary to survival, while brewing, well I know some would disagree, but it\'s not, so most people didn\'t take the time (or buy the equipment) to brew.