Acronym for potential of hydrogen. This is the measurement of a wine's acidic intensity. The pH scale ranges from 0 to 14, with 7 being neutral (neither acidic nor alkaline). Anything below 7 is considered acidic, and as the number decreases, the acidity intensifies. Winemakers use this scale to determine the exact acidity of their wines. White wine tends to be more acidic than red wine from the same climate, and therefore has a lower pH, usually around 3.3 to 3.0—anything lower and the wine is considered overly tart; anything higher and the wine is too soft and flat. Red wines range from about 3.3 to 3.6, which is why they're generally smoother and less crisp than white wines.