Final answer:
The pH of mash in brewing is influenced by the carbonate concentration in the water and the acidity of the malt. The ideal pH for mash is 5.2 to 5.6, and the pH scale is critical to categorize substances as neutral, acidic, or basic.
Step-by-step explanation:
The mash pH in brewing is indeed determined by the alkalinity of the water, specifically the carbonate concentration, as well as the acidity of the malt. In the context of brewing beer, this is a crucial factor as it influences the flavor, clarity, and color of the beer. Water alkalinity can buffer the mash and stabilize the pH, which ideally should be within the range of 5.2 to 5.6 for optimal enzyme activity. The malts, depending on their type, contribute certain levels of acidity which can counteract the buffering capacity of the water and lower the pH of the mash. Hence, the interaction of water's alkalinity and malt's acidity determines the mash's final pH.
Understanding the pH scale is essential in this context. Pure water has a neutral pH of 7. Substances with a pH greater than 7, like milk of magnesia (which is largely Mg(OH)2), are considered basic, while those with a pH less than 7, such as wine, are acidic. The pH scale is a logarithmic scale, meaning each whole pH value below 7 is ten times more acidic than the next higher value.