Washed Yeast Quantity

[Mrobson]

Bottled a brew on Sunday and washed the yeast, its been in the fridge until this morning, (planning a brew this evening) I have read that I don't need to make a starter as the yeast isn't that old, I have it split into two jars, would I need to pitch both or will one be enough?

Cheers.

 

[JonBrew]

the full answer depends on a number of factors such as:

1) size of batch the yeast harvested from
2) OG of the batch harvested from
3) OG and volume of the wort you intend to pitch into

however, in general terms, assuming you harvested from a 20'ish litre batch of 1040'ish OG beer or greater, you should be good to pitch into the same or greater OG beer.

Mr Malty provides a good calculator for re-pitching and a guide to estimating cell count etc

 

[JonBrew]

sorry, just realised what I said doesn't fully answer you question regarding pitching 2 jars or just one. mr malty will help guide you but I would say if you are pitching to a low OG or low volume of beer, one jar would probably do it. anything bigger I'd pitch both jars.

as I say, mr malty is the way to go. better safe than sorry.

 

[Mrobson]

Cheers, would I generally pitch both jars?

1) 20l
2) 1050 ish off the top of my head
3) Another 20l, est OG 1067

 

[DoctorMick]

I'm not going to answer your question either because I don't know the answer, sorry.

When I tried yeast harvesting I struggled with these kind of questions as without a lab it's really difficult to even estimate how much yeast you have. If you have a stir plate you could look at overbuilding, it's much easier to predict these kind of things.

What size jars did you use? How much yeast/trub is in the the bottom of the jar? My gut feel would be that 1 jar (assuming 500ml) would be enough for a 1050 brew, not so sure about the 1067. The MrMalty calc suggests 100ml yeast/trub (based on default values) is enough for 1.050.