Enzymes are biological catalysts. They are made by living things and they speed up the chemical reactions that happen in cells. Like any catalyst, an enzyme is not used up in the reaction.
Enzymes are used in the production of alcoholic drinks. The enzymes in yeast catalyse fermentation, in which sugar (glucose) is turned into ethanol and carbon dioxide. This is how wine and beer are made. In beer making, enzymes in germinating barley first break starch down into sugars that the yeast can then ferment.
A rate of reaction is measured as a quantity changing over time, for example the volume of carbon dioxide gas made each minute. To compare two rates as a ratio, divide one by the other. For example, if one flask makes 60 cm3 of gas in 2 minutes and another makes 30 cm3 in 2 minutes, the ratio of the rates is 2 : 1.