Also known as "strike water." In all-grain brewing, "liquor" refers to the hot water mixed with the grist to begin the mashing process. Liquor must be adjusted to specific temperatures to achieve the appropriate mash-in temperatures for a particular mashing style. At times, it is also treated to achieve the desired water chemistry or pH.
A brewer's term for water which has the correct balance of minerals to produce beer of the required palate. It provides the liquid medium essential for the fermentation process. The bulk of beer is water the type and quality is essential to the flavour of the final beer.