Harvested Yeast Starter Layers

I wouldn't worry about that little bit of trub. I think since the English strains are more flocculent than 3711 the yeast dropped out faster than the trub and the opposite happened with 3711.

Rdwahahb

 

I say use it all.

But are you sure about saving 500ml? From the photo I'm seeing about 50ml. Five hundred ml would be over a pint (16+ oz) and would be probably exceed 1 trillion cells.

 

First, as PortLargo said, your actual yeast is about 40-80ml of slurry... plenty if it's healthy, I'd not worry too much about the layering unless it has sat a couple weeks. Viability is indeed the same (on a % of total cells basis) in every layer, including the liquid layer on top; it's just that some layers contain a lot more yeast cells.

 

Decant the beer off the top. Stir, pitch into a session beer within 2 weeks.

If later, decant beer off top, make starter, let starter finish, put in the fridge for 3 days. Decant the beer again off the top and add to beer within 2 weeks.

Use the sediment. No need to split hairs.

 

We're saying the same thing, just differently. The liquid part of your sample has almost no yeast remaining, the slurry at the bottom is the good stuff. My guideline is to estimate ~2 billion cells/ml (of slurry) which is very close to what you have estimated through the starter process (I'm using quantity based on photo). I say you are in great shape to decant/pitch what you have. I would caution to take into account loss of active yeast if you delay more than a week or two and anything over that would probably benefit from re-starting. Sounds like you have a good technique to boost your count.

As for the white/tan layers, I see the same thing based on different strains. I'm not aware of any method to separate them, so it all goes in the fermentor for me.

It's never happened to me, but others will recommend leaving the jars sealed loosely . . . just in case those little guys get active again . . .

 

I suppose a graduated beaker would be best for this, but I would rather not have the extra step involved. So I just use the graduated marks on the mason jars. From your photo, it looks like the jar on the right has slurry about half-way up to the 100ml line. Not pretending this is really accurate, but it seems to give a ballpark figure that works out okay.