Question about developing a yeast library

[Jtc2811]

I have recently started hoarding samples of the yeasts that I use in brewing to save on time and money in the future. I have been using the Mason Jar approach advocated in the washing sticky, as it should be good for a couple of months after sealing the jar.

My question is this: when developing a sample to store (I usually go for about a 1.5L starter's worth, condensed into a small cake) how many times can I build up the yeast?

To put it another way, is the yeast made from a starter considered a second generation, such as that from making a beer? If I make a starter, split it, and make another, do I only have 2 more generations until I should think about getting rid of it? Or does the fact that the starter medium is a healthy yeast environment mitigate the mutation issue?

 

[Clementine]

My understanding of the yeast generation that a gentle 1.020-1.030 starter does not cause mutation and stress that a brew does and therefore does not count as a generation, however like you I would like other peoples opinions. I slant instead of washing and I have read re-slanting does not cause a generation to be added as the amount of growth is small, but I'm not sure about starters

Clem