How do breweries deal with yeast?

[aeviaanah]

I'm curious how breweries deal with yeast. Do they start with fresh every time? What is the pitching rate? Do they ever reuse yeast? How long do they oxygenate?

I'm aware of proper yeast care on the homebrew level, curious about the difference on a commercial scale.

 

[AK7007]

Most all use some form of in-line oxygenation to a defined ppm, though there are variations (coolships, etc)

Harvesting Varies wildly.

The most common way is to harvest yeast in the middle of the cake from the bottom of cylindroconical fermenters for 5+ generations, and then to re-buy when the strain begins to change.

Some very new breweries might buy every time if they don't know much about brewing.

Some places top-crop and literally never, ever buy yeast. Burton Union systems were a thing in the olden days to kind of automate the process.

Occasionally, you will hear of places that harvest yeast from bright tanks if they are using a strain that has trouble floccing.

"Wild" breweries manage much if not all of their yeast in-house. Crooked Stave is an example. Jolly Pumpkin doesn't even pitch yeast.

I'm not aware of any breweries that harvest from the bottom of flat lager tanks, but I do know that it was something that happened historically.

Also in the category of "is anybody still doing this?" is not exactly yeast harvesting, but breweries used to pitch actively fermenting beer into wort. (a version of krausening)

As far as pitch rates go, that can also vary even within a style. On one end, you've got The Alchemist pitching Conan at (0.5 million cells/ml)/degree plato, and on the other you've got guys pitching 3X that amount.

 

[LoopeyLoon]

The brewery I work at doesn't buy new every time. That gets very expensive. For a 10bbl batch they are buying about a 7-10 Liter pitch from Wyeast. After primary fermentation is done, we drop off the first part of yeast that comes out of the conical. Then collect the rest roughly 28-35 lbs of yeast into a yeast tank. And it depends on the style and what goes into the beer how many times they re use it. And we oxygenate inline as it is leaving the heat exchanger.