Decomposition / Hydrolysis
Japanese: 分解（加水分解）
Breaking large molecules into smaller ones. Most flavor changes in fermentation arise from enzymatic decomposition reactions.
Decomposition is a chemical reaction that breaks large molecules into smaller units. When water molecules participate, it is called hydrolysis—the form most decomposition takes in fermentation.
Miso's flavor is a gift of decomposition. Proteins become amino acids, starch becomes sugar, lipids become fatty acids—multiple enzymes work at their respective stations, dismantling the large molecules that composed the raw ingredients.
The small molecules born from this dismantling deliver umami, sweetness, and aroma to our senses. Decomposition isn't destruction; it's the act of unlocking a material's hidden potential.