Yeast: is it always the same?

[DannyD]

I always use starters and thus have, in the past, used one packet of Saflager W34/70 for about 5 batches. Now started with a new pack and it smells much different then the last? now i know smell is the last thing one can go on in a batche of green lager but still, can one always count it that the yeast that is in the packet is exactly the same as the previous packet? (comparing w30/70 with w30/70)

Or also the sample I toke from the krause and made a starter with, for the next batch, is exactly the same as the later?

Opinions?

 

[BigB]

Yeast is a living organism, so it will not be "exactly" the same from one package to the next. But the labs go to great lengths to minimize mutation and deliver to the customer the most consistent product possible... so, in general, there should be no perceptible difference for the home brewer from one package to the next.... but that also doesn't mean that no one ever falls asleep at the switch and doesn't monitor quality control to the point where a batch or two might get out in commerce that is somewhat different. A few years ago, there was a batch or two of Nottingham that made it into commerce that wouldn't fully attenuate.

As far as what you have in one starter as compared to a fresh package, no, there could be significant differences from mutation, growth, and stress.