Feeding yeast starter

[Roadie]

I brewed a while back using Conan and overbuilt by 100B cells which has been in a smaller mason jar. It's been five months and I want to feed this yeast to keep it healthy. I don't really need to increase cells over 100B. How much starter wort do I need to feed it and do I do this just like I was making a starter by using the stir plate?

 

[Brewmegoodbeer]

Use this calculator to estimate the amount of dry malt extract to use and how much volume: http://www.brewunited.com/yeast_calculator.php. for yeast viability, put in the date that you harvested the 100 billion cells into the mason jar.

 

[Roadie]

That's the calculator I use for determining how much I need to step up a starter for brewing but I've never used it for just feeding a pint of yeast. After plugging in the numbers it says my current starter is about 34% viable and to make a 1/2 liter starter, which of course will simply fill up my pint jar again. Easy peasy.