Ok so I built a stir plate. I made a starter with 800ml and 3/4 cup on mutons light dme. It has been spinning for 24 hours and the color is starting to turn white. How much yeast am I going to end up with. I pitched one vial of White Labs English Ale yeast.
What do you mean how much? How many yeast cells? How much slurry in ML?
Without running the exact calculations it should be about enough for a 1.045 - 1.06 beer(roughly) if you want exact cell counts you need to do the math(plenty of internet sites that will explain starters and cell counts).
The BEST way is to learn how much yeast you need and calculate out your starters otherwise your just guessing.
Also the amount of yeast you use contributes to flavor(underpitching or overpitching can both contribute different flavor profiles).