What is an ester quat?

An ester quat, short for ester quaternary ammonium compound, is a type of cationic surfactant. 

Cationic Surfactant: Surfactants are molecules that can lower the surface tension of liquids, allowing them to spread and mix more easily.

Cationic surfactants have a positively charged head group attracted to negatively charged surfaces like dirt and oil. This attraction helps lift and remove dirt during cleaning.

Ester: An ester is a functional group formed by the reaction between an alcohol and a carboxylic acid.

Quaternary Ammonium Compound:  This refers to a molecule with a central nitrogen atom bonded to four other groups, at least one of which is an alkyl chain (hydrocarbon chain).