The main difference between a soft curd and a hard curd is the amount of water remaining in the curd. Hard curds have very little water left in them. Whey is the name given to the fluid released from the curd. It is mainly water and contains most of the lactose and the albumin class of proteins. In this part of the process, salt is added to the cheese.
Salt is added for flavor and to inhibit the growth of undesirable microbes.
Large curds are formed as smaller curds are pressed together. Larger pieces of cheese are then formed. Ripening or aging . The cheese is allowed to ripen or age for various periods of time. During this time, bacteria continue to grow in the cheese and change its chemical composition.