Succinic acid
Japanese: コハク酸
An organic acid known as the umami component of shellfish. Also produced by yeast during sake brewing, contributing to the body of the drink.
Succinic acid is an organic acid known for its umami in shellfish. The deep flavor of miso soup with shijimi or asari clams owes much to succinic acid.
In fermentation, yeast produces succinic acid as a byproduct of alcoholic fermentation. Part of sake's body and 'fullness' derives from this acid. Small amounts also form during miso fermentation, contributing to complex flavor alongside amino acids and other organic acids.
As a TCA cycle intermediate, succinic acid sits within a fundamental metabolic pathway. That an element of core biological metabolism registers on our tongues as 'delicious' reveals a fascinating connection between metabolism and taste.