Large batches of Pyrex glass are produced in a specified compounding area of the production plant. Here, glassmakers follow formula instructions and add the required raw materials in the correct proportions into large tanks. Prior to use, the raw materials are pulverized and granulated to a uniform particle size. They are stored in batch towers. The materials are mixed together and heated to temperatures over 2,912°F (1,600°C). This high temperature melts the ingredients and allows them to thoroughly mix to create molten glass. However, the mixture typically requires longer heating—up to 24 hours—to remove excess bubbles that can lead to a weaker structure.