Reusing yeast

[Rod Hobbs]

So i am on my third similar style ale in a row, using the yeast saved from the previous batch (original was 11 g pack of nottingham). The amount of yeast left at the end of fermentation has increased each batch from about 1/2" in a mason jar, to about 1 1/2" in the second to around 5" in the current one. until now ijust added a bit of new wort and dumped the lot into the batch but now i am wondering if i have too much.

Q1 how do i know how much to use so that i dont over pitch
Q2 how many times can (should) i keep using this

Thx

 

[homebrewer_99]

If it's just washed yeast then you really don't need that much...1/2 cup maybe.

When I use slurry from one batch and pitch it directly into another batch I use 1 cup.

 

[Sparkncode]

Yep 1 cup from a previous batch takes off like a rocket. I did it with US05 and airlock actuvity in under 4 hours.
I'm certain a cup of slurry was more than enough for a normal beer on the other hand for a big high ABV beer i guess pitching on the whole cake from a previous brew would help.

 

[Northern_Brewer]

So i am on my third similar style ale in a row, using the yeast saved from the previous batch (original was 11 g pack of nottingham)...

Q2 how many times can (should) i keep using this

You need to be aware that Notty is a blend of different strains, and that blend will drift in subsequent generations. You can get a couple of generations out of it but don't be surprised if it starts to behave a bit weirdly at some point in the near future.