What Happens to Recycled Glass
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Recycled glass is sorted first by colour, since clear, green and brown glass are usually processed and sold separately, as colour affects what the resulting glass can be used for. Contamination from ceramics, stones or heat resistant glass is removed carefully, since even small amounts can weaken a finished product.
Clean, sorted glass is crushed into a material called cullet, which can then be melted down and reformed into new bottles and jars. Because glass does not degrade in quality when melted and reshaped, unlike some plastics, it can in principle be recycled this way indefinitely without losing its properties.
Cullet also has a practical advantage in manufacturing: it melts at a lower temperature than raw sand, soda ash and limestone, which reduces the energy needed to produce new glass. That is part of why glass with a high recycled content is generally cheaper and less energy intensive to manufacture.