How much harvested yeast should I pitch?

[dbrump]

Hi,
I have successfully collected 3 jars of harvested yeast from a 1.070 SG batch of beer.
My question is how much should I pitch into a new 5 gal batch of wort? The jars have been in a fridge for about a week and have settled leaving approx half an inch of yeast sitting in each at the bottom. I know there is a lot of calculations / formulas that can work this out but is there a 'basic rule of thumb'
Would half and inch of yeast/slurry (from a standard sized jam jar) be sufficient for fermenting 5 gallons??
If I used a stir plate would I initially need to start with less as it would multiply?

Look forward to hearing your thoughts.
Dave

 

[tre9er]

Hi,
I have successfully collected 3 jars of harvested yeast from a 1.070 SG batch of beer.
My question is how much should I pitch into a new 5 gal batch of wort? The jars have been in a fridge for about a week and have settled leaving approx half an inch of yeast sitting in each at the bottom. I know there is a lot of calculations / formulas that can work this out but is there a 'basic rule of thumb'
Would half and inch of yeast/slurry (from a standard sized jam jar) be sufficient for fermenting 5 gallons??
If I used a stir plate would I initially need to start with less as it would multiply?

Look forward to hearing your thoughts.
Dave

how many ML of yeast is in the jar? We don't know the jar size, so half inch means very little.

 

[dbrump]

how many ML of yeast is in the jar? We don't know the jar size, so half inch means very little.

I would say approx 60ml

 

[tre9er]

I would say approx 60ml

I'm not in front of mrmalty.com, but if you set it for thick slurry, high yeast concentration, I'm betting it will say you're golden for a mid gravity ale

 

[dbrump]

Cheers tre9er,

I'll pitch to Mr Malty's recommendations. I'll probably give my yeast a wake-up call with a starter before I pitch to be on the safe side.
Thanks for the help.