cells in WLP pure pitch

[Bobby_M]

Am i the only one freaking out over spending $20 for a pack of yeast? Kinda seems like White labs is saying screw homebrewers no? A real bummer because i Love WLP530 but due to the pricing i am looking at other options.

Well, $20 is overpriced for an overpriced yeast. Here's a version of that strain with about 50B extra cells.
https://www.brewhardware.com/product_p/oyl-028x.htm

 

[Bassman2003]

Makes starting a home yeast bank a worthwhile venture.

 

[McMullan]

I’m prepared pay $1 for 1ml yeast slurry that I could step up to produce something better.

 

[eshea3]

I’m prepared pay $1 for 1ml yeast slurry that I could step up to produce something better.

Or a slope like Brewlab does in the UK

 

[McMullan]

Or a slope like Brewlab does in the UK

Already got a selection of them, miniaturised too:

 

[eshea3]

Already got a selection of them, miniaturised too:View attachment 842344

Nice. How long do you keep those?

 

[McMullan]

Nice. How long do you keep those?

Ideally, they should be re-sloped after about 6 months, but they can maintain viable cells >12 months. These miniature slopes/slants are part of a storage experiment. The ‘gold standard’ for storing brewer’s yeast, microbiologically speaking. Significantly less (petit) mutation than freezing.

 

[Broothru]

What are the benefits of slanting/sloping yeast samples over freezing yeast samples in glycerol? I’ve been freezing yeast samples for several years and fortunately haven’t had any problems with thawing.

Is the main benefit with agar agar sloping the issue of storage temperature? Otherwise it seems like the prep process for freezing is less complex and the propagation prior to pitching is much less involved with less chance for contamination.

 

[McMullan]

What are the benefits of slanting/sloping yeast samples over freezing yeast samples in glycerol? I’ve been freezing yeast samples for several years and fortunately haven’t had any problems with thawing.

Is the main benefit with agar agar sloping the issue of storage temperature? Otherwise it seems like the prep process for freezing is less complex and the propagation prior to pitching is much less involved with less chance for contamination.

Freezing is for long-term storage and, if done properly, a lot more complicated than storing on nutrient agar slopes at fridge temperature. Slopes are for storing more readily accessible quality-controlled cells on an ongoing basis for up to 12 months. No freeze-thaw stresses or dehydration and QC’d prior to sloping therefore ready to go. The agar provides a matrix through which nutrients slowly diffuse to support the yeast cells during growth, shipping and storage. Much kinder conditions with a much lower mutation rate. Why it’s been a standard format for commercial breweries for years, in fact. A meaningful comparison between frozen yeast cells (especially using crude home-brew hacks) and QC’d yeast cells stored in agar shows why slopes are an industry standard.

 

[Broothru]

Is it possible/practical to freeze agar slants for extended storage if glycerol was used as a substitute for mineral oil to prevent cell wall rupture? If an agar slant is viable with healthy yeast for 6~12 months at refrigerator temperatures, could freezing extend this by years with less concern for infection or genetic drift/mutation that can occur in “home freezing” (non-laboratory) settings?

 

[McMullan]

Is it possible/practical to freeze agar slants for extended storage if glycerol was used as a substitute for mineral oil to prevent cell wall rupture? If an agar slant is viable with healthy yeast for 6~12 months at refrigerator temperatures, could freezing extend this by years with less concern for infection or genetic drift/mutation that can occur in “home freezing” (non-laboratory) settings?

No.

 

[smcinco]

Already got a selection of them, miniaturised too:View attachment 842344

Awesome. Do you ranch under a flow hood or with an alcohol lamp on the bench? Would love to hear/see your process.