Do I need to make a starter with washed yeast?

[Kaz]

I have my first several mason jars of washed yeast in the fridge, WLP400. This yeast was washed about 3 weeks ago. When I look into Mr. Malty, under repitching slurry, it just gives me a volume in mL of slurry to pitch and nothing about making a starter with it. It seems to me that a starter would be a good way to go in order to insure viability and get the yeast active. What do folks do with the washed yeast and how do you go about figuring your starter volumes.

 

[SavoryChef]

Check out yeastcalc.com and yes a starter is good.

 

[Transamguy77]

I do both, most of the time I make a starter especially if the yeast has been in the fridge for awhile. Some times I have a spur of the moment brew and I'll pitch 2 jars (I use the small 6oz ones) and have not had a problem.

 

[solbes]

Generally no I would say. But it really depends on how long the washed yeast has sat in the fridge. Anything under 3 weeks and I've experienced very short lag times. I generally get them active again with a starter if they've sat for more than a month in the fridge.

 

[diS]

Purpose of starter is dual: activating and growth of yeast. I would surely make starter for activation, question is how many cell do you have and how many do you need.
Usual though is that we get 1-2 billions/ml by washing, it is hard to tell without microscope but you will learn it with experience. As said you can expect longer lag phase, but it also depends on how many cells do you start with.

Good starting point would be 1B/ml decreased by viability, from then you can adjust starter volumes and no. of steps in http://www.yeastcalc.com/

 

[Kaz]

I went with a guess of about 150billion cells in my 100mL slurry. Decreased that using a 60% viability and then built up a .8L starter to get me to about 270billion cells for my pitch rate. Thanks for the help!

 

[Britinusa]

I am very interested in this! how would you know what the cell count is?

 

[acidrain]

I am very interested in this! how would you know what the cell count is?

Here, let me help you with that...

we get 1-2 billions/ml
Good starting point would be 1B/ml decreased by viabilityhttp://www.yeastcalc.com/

 

[WoodlandBrew]

1 billion per milliliter is a reasonable guess if you don't have a microscope, but be aware it can vary quite a bit. Cell density from 400 million per ml up to 2 billion per ml is pretty typical for me to see.

The beer that the slurry came from seems to effect the viability much more than time. I've seen a drop of 10% viability for every 1% ABV above 6. Fruit also seems to be a very effective yeast killer.

Here is some data on viability in the fridge:
http://woodlandbrew.blogspot.com/2012/12/refrigeration-effects-on-yeast-viability.html

And the effect of fruit on viability.
http://woodlandbrew.blogspot.com/2012/12/how-fruit-effects-yeast-viability.html