As proper curing greatly increases concrete durability and strength, it is one of the most important steps in concrete construction. Concrete hardens as a result of hydration: the chemical reaction between water and cement. Therefore water has to be available and the concrete’s temperature has to stay within a suitable range. During the curing period, 5 to 7 days after pouring, the concrete surface has to be kept moist to permit the hydration process. New concrete can be wet with sprinklers, soaking hoses, or covered with wet burlap. It can also be coated with commercially available curing compounds, whose purpose is to seal in moisture.