a
reference to an ancient practice used in the
process of making beer. Beer has long been a popular beverage as it does not deteriorate during long periods of storage and is adaptable to all climates. In making beer, one adds
yeast to the ingredients to allow the mixture to ferment, that is, to
turn into
alcohol. As part of this fermentation
process the liquid was placed in a container and buried in the
ground. Keeping it in the earth (which is
cool) ensured a correct and stable temperature for the
process. Civilizations since ancient
times have put beer into earthen vessels and buried it in the earth, or into wooden barrels and half-buried them in the floors of cellars, where it remains
cool.