Now that sounds like a tasty beer. What's your pitch rate?

To be completely honest, I do not use yeast calculators. In my humble opinion, yeast calculators are one step above useless. The only real way to know one's pitch rate is to count, and I am usually too busy to bother with counting. I pitch mostly based on experience with a strain, as no two strains perform exactly the same when pitched into the same wort.

With that said, I usually pitch the equivalent amount of yeast cells that can be grown in a one liter 7.5% w/v (roughly 1.030 S.G.) starter into five gallons of wort (at most 200 billion cells). However, when I underpitch, I cut that volume by two thirds. My standard starter volume when pitching Young's strain into five U.S. gallons of ordinary bitter wort is 300ml grown from slant. If the maximum cell density for a yeast culture is 200 million cells per milliliter, then a 300ml culture has at most 300 x 200,000,000 = 60 billion viable yeast cells, which is less than 1/3rd the normal suggested pitch rate for a 1.040 beer. According to theory, one should pitch 1,000,000 cells per milliliter per degree Plato; hence, I should be pitching at least 1,000,000 x 19,000 (five gallons in milliliters) x 10 = 190 billion cells.