how many cells are here?

[Veedo]

Beginning of april i made a 1.5 liter starter on a stirplate to pitch into a cream ale. Before i pitched i cold crashed the starter, decanted, and filled this vial up. Now i would like to make another starter from it, but I'm not sure how many cells are here. 20b? I'm familiar with yeast calc and mrmalty, but im just curious to what everyone else does to guesstimate.

I also have harvested slurry from this batch i could use to make a starter, but that could be even harder to calculate. 100ml of slurry - .5 liter step - 1 liter step?

 

[lud]

Someone please correct me if I'm wrong but the number I use is one million cells in one milliter.

 

[Geordan]

A safe number, judging by Jamil's calculator, is 2 billion cells per ml. My decidedly unscientific approach is to usually use water in a container of the same size and shape to estimate the liquid volume of the yeast level, and multiply the result in ml x 2 billion cells x 0.x, where 0.x represents the viability of the yeast (usually taken from Jamil's calc as well.) Then, hop on over to YeastCalc and set up your steps!

 

[TarheelBrew13]

There's no way to figure this out that I'm aware of. Sure you can guess but it's just a guess and it could be way off. For this reason, I use a microscope.

 

[lud]

Thanks..I meant billion/mil. Viability decreases with age...adjust accordingly. Will I stay awake at night knowing I won't be nuts on accurate because I don't have a microscope? No.

 

[corax]

There's no way to figure this out that I'm aware of. Sure you can guess but it's just a guess and it could be way off. For this reason, I use a microscope.

How do you distinguish the dead cells from the live ones? Vital stain?

 

[passedpawn]

How do you distinguish the dead cells from the live ones? Vital stain?

Methlyene blue or Alkaline Methylene Violet. Here's some pics of the violet in action under my scope:

https://www.homebrewtalk.com/f163/pics-yeast-under-my-new-scope-273342/index8.html#post4015635)

 

[Veedo]

pretty much a guessing game like i thought then. i entered 20b for a starting point in yeastcalc. ill start with a .5 liter step, and go from there.

what kind of scopes do you guys have?

 

[passedpawn]

pretty much a guessing game like i thought then. i entered 20b for a starting point in yeastcalc. ill start with a .5 liter step, and go from there.

what kind of scopes do you guys have?

Olympus.