buffer

Does yeast need potassium during growth, or during anaerobic fermentation, or both? Or worse, do they want it as soon as possible when pitched? I ask because the popular BOMM mead recipe suggests adding potassium carbonate at pitch to provide potassium and buffering, and I'm thinking about...

I've brewed 21 all grain batches with great results and have never worried about my mash pH until recently. I added 1 tablespoon of Five Star's 5.2 mash stabilizer to each of my last two beers, an ESB and American Amber. Before kegging, both beers tasted young but right where they should be...