Should I step up starter?

[RUNningonbrew]

I am making an Imperial IPA this evening with a OG of 1.098. I made a 1 liter starter last night with some california ale yeast I washed from a previous batch (about 2 cm worth of 2 mason jars) and its been on my stir plate for 12 hours. Mr. Malty says I need 300 billion cells, should/can I pitch another liter of wort on top of the yeast and will it be ready by tonight? Thanks.

 

[WoodlandBrew]

Adding another liter of wort will get you closer, but it likely isn't going to finish by tonight. The minimum time I have seen is 24 hours.

You probably have about 150 billion cells based on growth rate. Another way to guestimate the number of cells is by the volume of the yeast that settles to the bottom. For me it's between 250 million per ml to 1400 million per ml. Some people use 1 million per ml as an estimate.

Instead of stepping up your starter you can step down your wort.

Pitch the approximately 150 billion cells into 2 gallons of your 1.098 wort and let it go for 24 hours. Then add the last 3 gallons of wort. You'll want to make sure to store your wort as sanitary as possible. See the no-chill method for some ideas. I use a pressure caner to store the wort before it is inoculated. Other people use expandable water bottles.

 

[RUNningonbrew]

I will let it settle and see how many ml I have, or maybe I will just go buy another vial of yeast to be on the safe side

 

[RUNningonbrew]

I know this isn't the best picture but is this enough yeast? This is after about 16 hours on stir plate