How Glass is Made

Discover the steps of the glass-making lifecycle

We love glass.

It starts life as sand, goes through fire and becomes a natural, beautiful material that safeguards your food and drink and is good for the environment.

Discover the anatomy of a glass container

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The Steps

Step 1: The recipe

We use sand, limestone, soda ash and recycled glass (cullet) in our glass recipe. The combined ingredients are sent to the furnace to melt.

Step 2: Melting

The furnace heats the batch mixture to about 1500 degrees Celsius, creating molten glass.

 
Step 3: Molten Glass Separation

The molten glass is removed from the furnace, cooled to a uniform temperature and cut into “gobs” to form glass containers.

 
Step 4: Forming & Moulding

We divert the gobs into forming machines and then mould them into beautiful, functional O-I glass containers.

 
Step 5: Annealing

Formed containers pass through the lehr, a machine that reheats and gradually cools them to relieve any stresses and strengthen the glass.

 
Step 6: Inspection

Finally, we inspect our glass containers to make sure they meet our high quality standards. We recycle and re-melt any containers that fail to meet these standards.

 
Step 7: Packing & Shipping

Once the bottles have passed inspection, they are packed on pallets.  Quality bottles and jars are then distributed to customers around New Zealand to be filled with food and beverage products.

 
Step 8: Recycling

Once the glass bottle or jar is empty, it can be recycled either through kerbside recycling or a public recycling facility. Glass is a unique packaging material as it is 100% infinitely recyclable.

 
Step 9: Beneficiation

Beneficiation is the process of treating raw materials to improve their properties.  All the glass comes in from around New Zealand to have the contaminants removed, such as crockery, window glass, metals and so on.  The finished product is then shipped to O-I NZ and the process begins again.

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