How much yeast for 80l brew?

[McMullan]

Haven't worked out how to avoid the council yet.....

MM: "Naw playin' on de merry-go-roun' for de next 48 'ours, kids. Dat goes for yer teenagers too. But i'd loike yer al' ter keep it spinnin' nonstop an' really fast durin' dis time. Al' 48 'ours mind. Proobably best if yer organise yerselves into shifts."

They'll do unimaginable things for starters!

 

[ManseMasher]

Just to get this right in my head - if I use two vials in a 5l starter and use a stir plate, I can get around 900 billion cells? I take it after the starter is done I can pour off the majority of the spent wort, shake the remainder to get everything in suspension and then pitch? The below is a quote from someone quoting Jamil Z....

'Please note that this study was done with no added oxygen. Adding oxygen with a stir plate or by shaking will roughly double the amount of growth you get. Also keep in mind that fresh yeast was used in the study, so if your yeast is older then you won’t get as much growth.

To find the maximum size starter you can make with a given container size, read the last number in that column. For example, the maximum starter size you can make in a 2L starter is 300 billion cells (with no aeration).'

 

[McMullan]

Just to get this right in my head - if I use two vials in a 5l starter and use a stir plate, I can get around 900 billion cells? I take it after the starter is done I can pour off the majority of the spent wort, shake the remainder to get everything in suspension and then pitch? The below is a quote from someone quoting Jamil Z....

'Please note that this study was done with no added oxygen. Adding oxygen with a stir plate or by shaking will roughly double the amount of growth you get. Also keep in mind that fresh yeast was used in the study, so if your yeast is older then you won’t get as much growth.

To find the maximum size starter you can make with a given container size, read the last number in that column. For example, the maximum starter size you can make in a 2L starter is 300 billion cells (with no aeration).'

All other things being optimal, it's probably a reasonable questimate, depending on the yeast strain, its viability and vigour, as well as the starter wort environment, really. This table is a very general guide that is a good starting point to figure out what you might need. The only way to know for sure how many viable cells you have, is to use a microscope and some basic technique. Honestly, this is not that difficult. I'll have my lab set up early in the new year. If you want a demonstration I'm happy to provide one. I think your best option is 10L with aeration. Yes, you could let them flocculate and pour off the excess spent wort and resuspend them (in some fresh wort) then pitch. If you're strict with your good method practices, you might only have to do this 2-3 times a year. There are some tricks to use when you have conicals, too. Like letting the trub settle overnight to be racked off before pitching the yeast. Then you harvest more yeast after primary :thumb:

 

[MyQul]

. Like letting the trub settle overnight to be racked off before pitching the yeast. Then you harvest more yeast after primary :thumb:

I do this when no chilling. I let my wort chill ovenight and as a side benefit a lot of trub stettles out too. So I rack the wort off the trub into a second fermenter then pitch the yeast. Usually works very well.