Glass is mainly composed of four ingredients –sand, soda ash, limestone and cullet (recycled glass), with as much as possible of the recycled glass to bring down the melting temperature. Accurate weighing of these ingredients is crucial. The raw materials are fired to 1520 degrees centigrade, producing molten glass. This flows out of the furnace and is cut into individual gobs (globules of molten glass) which are then fired into a forming machine which temperature reaches 1100 degrees.

After being formed the containers are given a ‘hot end’ coating to maintain their strength. The glass is then sent through a lehr – a long oven that ‘anneals’ the glass by raising its temperature to 600 degree centigrade. This removes any stresses that have been created in the container during production – giving the glass maximum strength. The temperature in the oven gets