I have a question about yeast. It may have an obvious answer, but here it goes. I have been reading that washed yeast will only last a certain amount of generations before you loose the profile/umph of that particular strain. How do breweries create and maintain their special yeasts without loosing their flavor or do they have to constantly make new yeast? If they do "make" yeast how do they do it? Just curious. Thanks all.
yeast production ?
- Thread starter dmbryan
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SD-SLIM
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Yeast continue to mutate and change in to yeast that have different flavors or that just dont work as well as they should....so homebrewers or breweries take a sample of there good yeast and culture it in petri dishes and then use a step process to get it to a large enough starter.
Some smaller breweries regularly buy new, clean batches of yeast from White Labs (not for every fermentation, but regularly). One brewer here in Chicago told me that's what they do.
Larger brewers may have a yeast lab they maintain. Dogfish Head does (I saw that on the Discovery channel show).
Larger brewers may have a yeast lab they maintain. Dogfish Head does (I saw that on the Discovery channel show).
Also, labs are able to maintain cultures almost indefinitely, without mutations, by freezing them at temperatures of -80° or cooler.
Freezers capable of such temperatures are not at all realistic for homebrewers, although a very cold chest freezer that DOES NOT self-defrost can store yeast cultures for up to a few years or so, IIRC.
Of course, it's never as simple as just sticking a yeast culture in a freezer, because, for instance, the ice crystals that form will pierce the cell walls and kill the yeast cells. So a cryprotectant must be used to prevent this, and certain procedural and sanitary practices must be adhered to while preparing, freezing, and thawing the culture.
Freezers capable of such temperatures are not at all realistic for homebrewers, although a very cold chest freezer that DOES NOT self-defrost can store yeast cultures for up to a few years or so, IIRC.
Of course, it's never as simple as just sticking a yeast culture in a freezer, because, for instance, the ice crystals that form will pierce the cell walls and kill the yeast cells. So a cryprotectant must be used to prevent this, and certain procedural and sanitary practices must be adhered to while preparing, freezing, and thawing the culture.
...and medium-size breweries (Gordon Biersch comes to mind) may have a propagation system but no deep-freeze storage, so they buy a fresh culture from a lab every few weeks.
