The essential components required in water for sake brewing are "potassium," "phosphorus," and "magnesium." These elements serve as sources of nutrition for yeast and koji mold, aiding in their growth and proliferation. When these components are deficient, alcohol fermentation may not proceed properly.
On the other hand, representative unwanted components include "iron" and "manganese." "Iron" can cause the appearance to become reddish-brown and result in unpleasant odors. "Manganese" accelerates discoloration due to ultraviolet radiation. Additionally, unwanted components may encompass precious metals, ammonia, nitrites, nitrates, organic substances, and, more recently, wild yeast.