The Wealth of Nations by Part 5 Chapter 2 Page 167

things which the established rules of decency have rendered necessary to the lowest rank of people. All other things I call luxuries, without meaning by this appellation to throw the smallest degree of reproach upon the temperate use of them. Beer and ale, for example, in Great Britain, and wine, even in the wine countries, I call luxuries. A man of any rank may, without any reproach, abstain totally from tasting such liquors. Nature does not render them necessary for the support of life, and custom nowhere renders it indecent to live without them.

As the wages of labour are everywhere regulated, partly by the demand for it, and partly by the average price of the necessary articles of subsistence, whatever raises this average price must necessarily raise those wages so that the labourer may still be able to purchase that