Grapes grown on limestone soils are commonly associated with which effect on acidity?

• A. Lower pH (higher acidity)
• B. Higher pH (lower acidity)
• C. No change in pH
• D. Variable pH

Answer: (A)

Grapes’ acidity is shaped by how the soil affects vine vigor, water stress, and ripening rate. Limestone soils are well-drained and can create a cooler, slightly stressful site for the vine. That slows ripening and helps preserve organic acids such as tartaric and malic in the grapes. When acidity remains high, the must has a lower pH (more acidic). So, the common association is with a lower pH, i.e., higher acidity, in grapes grown on limestone. This pattern contrasts with concepts of higher pH (lower acidity), no change, or highly variable pH, which don’t align with how limestone soils influence acid retention in the fruit.