Originally Posted by Patirck
Does anyone know how commercial breweries do this? They seem to have some special equipment that I have seen but I don't know if they are "making starters". I have seen them dump yeast from the bottom of the cone into what looks like modified kegs.
Not all commercial breweries do it the same way. Almost all of them will reuse yeast from the previous batch, but they can really only get 5-10 uses out of this yeast.
When they need a fresh source of yeast, they effectively use a starter, though they won't call it that - they "propagate" yeast. If they're big enough to have their own lab, they'll start from literally a single cell in order to ensure they're maintaining a relatively pure and consistent culture. Smaller breweries will generally rely on specialized labs (eg Wyeast/White Labs) to do this for them, and the lab will either provide them with a pitchable amount (for fairly tiny breweries), or a "brewery"-sized slurry that basically moves from the lab to the brewery to be built up for the final few steps. Some breweries even rely on other breweries for lab services/yeast maintenance.
Basically, we as homebrewers rely on the same lab services that smaller breweries do. The only differences are that we buy our yeast in much smaller amounts, and that we are limited to the strains that stores happen to carry, which in turn is generally limited to the labs' specific year-round and seasonal homebrewer offerings, rather than having access to their entire (public) yeast bank, or having the lab maintain our own proprietary yeast strain.
But breweries simply cannot maintain healthy yeast by constantly re-pitching, and if they want their yeast to remain even remotely consistent, they have to maintain pure cultures which requires storage in absolutely miniscule amounts (such as in slants), and the occasional culturing from literally a single cell. So whether they do it themselves, or have an outside lab handle it (like MOST of us), the yeast is ultimately built up from a single cell to pitching rates of millions of cells PER MILLILITER of wort. While they may not call it "making a starter", pretty much every modern brewery does it.