What mineral helps filter iron from ground water, affecting bourbon maturation?

Limestone plays a crucial role in filtering iron from groundwater, which directly impacts the water used in bourbon production. The water's mineral content is essential for the fermentation and maturation processes. When groundwater passes through limestone, the natural filtration removes unwanted minerals like iron that can negatively affect the flavor and color of bourbon. Additionally, limestone water is known for having a balanced mineral profile that contributes to the desired characteristics in bourbon, such as smoothness and complexity. The presence of calcium and magnesium from limestone can enhance the fermentation process, leading to a more flavorful end product. Overall, limestone not only influences the quality of the water but also enriches the bourbon's maturation process, making it a critical factor in bourbon production.