Which ingredient makes up over 90% of beer and significantly affects its taste?

Water is the primary ingredient in beer, comprising over 90% of its total composition. Its significance cannot be overstated as it plays a crucial role in the brewing process and the final taste of the beer. The mineral content, pH level, and overall quality of the water can dramatically influence the beer's flavor profile. For example, water with a higher mineral content can enhance bitterness or sweetness, while softer water may result in a more delicate taste.

Other ingredients such as malt, hops, and yeast are also essential in brewing, each contributing their own unique characteristics. Malt provides the sugars needed for fermentation, hops add bitterness and aroma, and yeast is responsible for the fermentation process. However, the foundational role of water makes it the most significant ingredient affecting the overall taste of beer.