I missed seeing this thread when I searched for this topic a moment ago. As a result, I just posted a separate thread to the effect that the Activators were going to be discontinued. I emailed a representative at WYeast to confirm that that these packets will not longer be produced. As on the other thread, I'd urge those who make regular use of the Activator packs to email WYeast urging them to reconsider their decision.
Good Lord, my LHBS sells the Activator smack packs for 4.50.
Do you mean Propagator packs?
...Then I dilute it with colled, boiled water and store it in small canning jars ...
Bierenliefhebber said:Thanks for bringing that up; this reminds me of a question that popped into my mind when I looked at the yeast-washing instruction. Having had a bit of laboratory experience with cell culture, I was very surprised indeed to see the yeast being washed, and even stored, in plain water. Why water? Why not an isotonic Ringer's solution with some kind of buffer system to maintain the pH? My experience with other cell systems is that plain water is deadly to cells. Even though yeast cells are apparently tough enough to withstand being put away in plain water, wouldn't a kinder environment increase their viability? A buffered salt solution would be cheap and easy enough to make.
If plain water were deadly I doubt the dry yeast companies would recommend rehydrating in tap water.
Bierenliefhebber said:Now, the cells I was culturing were kidney cells and osteoblasts which, unlike yeast cells, don't have a cell wall to protect them from the environment. If the ion concentration isn't just so, these cells willl either shrivel up and die or they'll swell up and explode. Obviously yeast cells are much hardier, and if they have to, can live in pure water which would cause mammalian cells to explode. Nonetheless, as a biologist, it still seems to me that they'd be happier and live longer if they were stored in a less hostile environment. Ringer's solution is nothing more than a buffered solution containing salts of sodium, potassium and calcium in about the same concentrations as are found inside a living organism. This could easily be sterilized by boiling, just like water, and should be a better storage medium. But, hey, I'm just thinking out loud here, I have zero actual experience with washing and storing yeast.
I'm surprised to learn that Propagator packs are relatively rare. At Brouwland, which is virtually the only supplier of homebrew supplies in Belgium (and they act like it, too), they carry, or did carry, more varieties of the Propagators and these were generally fresher than the Activator packs. Because of this limited experience, I had had the mistaken impression that the Propagator was actually the more popular of the two. Well, good advice about splitting Activator-generated starters and setting some aside for later. Guess I need to learn to do this.
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