Starters

[Love_In_Da_Brew_Zone]

Ive been creating yeast starters using a smack pack, 2 cups of water and 1/2 cup of DME in a 1000ml flask on a stir plate 24 hrs in advance of my 5 gal brew for years........but I just had someone ask how I knew that I was ending up with enough yeast for my brew.
I can easily calculate the required number of cells using any one of a million calculators that are out there, but it did occur to me that I have no idea really how many I am pitching......is there an easy way to figure that out?

 

[BlueHouseBrewhaus]

Short of using a microscope, you can't know for sure. The same calculators that tell you how much you need will also estimate how many cells you create for a given yeast age, volume and gravity. I use YeastCalc, which actually has two different algorithms to choose from. One is more conservative than the other.

 

[Braufessor]

The total number of yeast cells (provided it is within reason) is not nearly as important as pitching healthy, actively fermenting cells. When a starter is about 18-24 hours in, at high krausen, and you pitch it to your wort - the doubling time of the cell count is happening rapidly. Being off by a doubling time or two becomes somewhat irrelevant.
Active, healthy yeast that is growing fast is better than more yeast that is dormant or unhealthy and takes longer to get going again.

If you are brewing a really big beer, or a bigger lager, etc..... then cell count becomes more of an issue. But for a "normal" beer, a healthy smack pack into 1L of starter the day before you brew is perfect.