Definition - What does Liquid Oak mean?
Liquid oak is an extraction from oak which is available in liquid form used as an oak substitute. It is used to instantly add oak characteristics to a finished wine. As this is a more inexpensive alternative to using oak barrels, it is often used for lesser quality wines.
WineFrog explains Liquid Oak
Liquid oak is an oak substitute which is often utilized to add oak characteristics to wines of lesser quality. A desired amount of liquid tannin can be added to a finished wine. It works by binding with the alcohol of the wine. In order to create a more well-rounded oak influence on the wine, liquid oak is often used in combination with a dose of oak powder.
Liquid oak is one of the three major oak substitutes used instead of expensive oak barrels, the other two are oak chips and oak staves.