Amylase Activity

Amylase activity quantifies koji's power to break starch into sugars. Amazake sweetness and white miso sweetness depend heavily on this activity.

Generally, raising temperature to 38-42°C in the latter half of koji making promotes amylase production. Amazake koji emphasizes amylase; miso koji balances with protease. Same koji mold, but temperature control shifts the enzyme balance — herein lies the technique and depth of koji making.

Amylase includes alpha and beta types: alpha-amylase randomly cleaves starch chains while beta-amylase releases maltose from chain ends. This two-stage breakdown creates miso's natural sweetness. The coordinated action of enzymes generates the complex flavors characteristic of fermented foods.