pH drop

FACTS
occurs very rapidly over the first 48 hours of fermentation
usually spans at least 1 pH unit over fermentation period
optimal pH for yeast is pH 4.0

CAUSES
affected by any factor that affects yeast growth
due 10% to formation of carbon dioxide
due 20% to formation of organic acids (lactic, succinic, oxalic)
due 40% to absorption of alkaline substances such as phosphates and amino acids

EFFECTS
extreme drop produces a less mellow, more astringent, drier-tasting beer