Assume I know how to properly ferment grain and distill it into whisky, and that I have all the necessary equipment. If I want a "sour mash" whisky, how would I go about it?
From a bit of research, it seems that the term "sour mash" simply describes some sort of process where the distiller saves a bit of the old mash (maybe he/she "cultures" it somehow, to grow enough live yeast?) and adds it to a new batch to facilitate fermentation?
Is there anyone familiar with the process who could describe how to apply it to an existing hypothetical small-batch whisky making operation?