As the title says, yeast really is blowing my mind! I have gone to the trouble of making myself a stir plate and just ordered Wyeast for the 3 beers I intend to make, but how the hell do I calculate the yeast that is required. I have had folk kindly help but I still cannot fathom it. I know there are calculators but for example how can you input the numbers if you haven't brewed a beer before and don't know the hydrometer readings, bearing in mind your making the starter a few days in advance. Also if your making a starter from one sachet of yeast how do you know when it is big enough for the beer you are planning to make. I am guessing to much is possibly as bad as too little yeast when pitching. Does it go on how much volume in mls you have in the flask of DME And does anybody harvest the yeast off the beer and harvest and freeze. Please feel free to think I am being dumb as I feel it at the moment..