It is made by the action of the yeast plant on wet sugar or starch--a process called _fermentation_.

Usually the sugar or starch is in the form of the juice of fruits; or is a pulp, or mash, made from crushed grains like barley, corn, or rye.

As the spores of this yeast plant are floating about almost everywhere in the air, all that is usually necessary is to let some fruit juice or grain pulp stand at moderate warmth, exposed to the air, when it will begin to "sour," or ferment.
Wine.

When the yeast plant is set to work in a tub or vat of grape juice, it attacks the fruit sugar contained in the juice, and splits it up into alcohol and carbon dioxid, so that the juice becomes bubbly and frothy from the gas.

When from seven to fifteen per cent of alcohol has been produced, the liquid is called wine.