Brewers make wort, yeast make beer.
If you have been homebrewing for even a short amount of time you have probably heard that statement. As much as we would like to think that we are in control, it is our microscopic little friends that determine the quality of our batch; brewers are little more than glorified yeast wranglers. Thus, when fellow homebrewers ask me what they can do to improve the quality of their beer the first thing I always tell them is: “make a yeast starter.” Proper amounts of healthy, happy yeast make delicious beer free from off-flavors; simple as that.
Time to let you in on a little secret: yeast are not the only things that make beer! Myriad organisms such as Brettanomyces, wild Saccharomyces, Pediococcus, and Lactobacillus will happily feast upon the wort you just created and leave you with beer (and those are just the organisms that produce favorable characteristics). Indeed, it is these organisms that folks interested in making sour or funky beers will harness to produce the character they are looking for. However, whether you are making a clean beer with “regular” yeast or a sour/funky beer with these other organisms, one thing remains the same: proper amounts of healthy, happy <insert organism(s) of choice> make delicious beer free from off-flavors. When folks tell me their sour mashes go bad I liken it to folks saying their regular beers went bad, only to find out they pitched a single vial of old yeast into 1.090 OG wort at 95ºF. A little bit of preparation practically guarantees a successful souring; whatever your organism of choice is, make a starter!
If you have been following along with Year of the Sour Mash you will know we are primarily interested in the fast, clean souring of Lactobacillus to sour our mash/wort. Whether you are pitching a pure culture of Lactobacillus or growing a wild culture from grains, I have created this Lactobacillus starter guide to help you propagate the quantities needed to ensure your beer sours cleanly.