The increasing popularity of glass containers

The use of glass as a packaging material for food, beverages and pharmaceuticals is growing.

Much of this is due to its environmentally friendly nature – glass can be reused endlessly without losing quality,  helping to reduce waste and resource depletion. The growing use of glass recycling schemes like Return and Earn (NSW), Container Deposit Scheme (VIC) and Containers for Change (QLD & WA), offering cash returns for glass are testament to the drive to recycle this versatile material.

Even if glass does go to landfill, it doesn’t release harmful greenhouse gases like methane, nor does it negatively impact marine life. So as Australia moves away from single use plastic, production and consumption of glass is growing. Glass manufacturing in Australia is set to grow from 1.51 millions tonnes in 2025 to 1.9 million tonnes in 2030, a compound growth of 4.73%¹.

Glass containers have a lot of jobs to do:

• They must keep their contents fresh, and remain air tight
• They must keep their contents safe from contamination by other products, acting as an impenetrable barrier to ensure that products reach consumers in their original state
• They must be strong enough to resist breakage or shards that could harm consumers as well as spoiling and wasting their contents.
• They must remain their integrity and not leach their own component chemicals into the products they hold.
• They may also be a part of a company’s branding – with shape, colour and treatments helping consumers to identify their favourite product.

Why temperature is important

Every part of the manufacturing process relies on precise temperature control.
Quality starts in the furnace, where molten glass is made. Thermocouples measure this high temperature accurately.

Creating glass containers

But if the glass is to be made into containers, it goes through another process – formation – which requires different technology to monitor temperature. Containers are created by putting ‘gobs’ (measured amounts) of molten glass through a blow and blow process or a press and blow process (depending on the shape required – bottle or jar). The gobs are shaped in a mould and formed by blowing in compressed air. Once formed, the containers are slowly reheated in an annealing lehr (or kiln) and cooled to below the strain point of glass, so that the finished product has the desired strength profile.

The temperature during the annealing process is critical to the quality of the finished item. Incorrect temperatures can lead to product flaws such as bubbles, cracks and incorrect dimensions, that compromise the efficacy of the container to hold foods, liquids or medication.

IR Cameras and Pyrometers: No-Touch Temperature Sensing

Formed containers can’t be touched, so manufacturers rely on non-contact temperature sensing.
Two technologies make this possible:

IR Cameras

• Map temperature across an entire area

• Provide visual thermographic output

Pyrometers

• Measure temperature at a single point

• Provide fast, precise readings

Both detect thermal radiation and convert it into usable temperature data.

Using Temperature Data to Improve Quality

Manufacturers track temperatures at critical control points. Examples include:

• Checking mould temperatures

• Confirming correct cooling rates

• Ensuring uniform heat during annealing

Real-time data helps operators adjust processes instantly to maintain correct specifications.
Stored data helps identify long-term patterns, such as drift in lehr temperature, so issues can be fixed before faults develop.

After production, skilled staff perform visual inspections, strength testing, leak testing and chemical resistance checks. If issues appear, temperature records from IR cameras and pyrometers help trace the cause.

Delivering High-Quality Glass Containers

As demand for glass grows, so does the need for consistent quality.
IR cameras and pyrometers play a crucial role in monitoring temperature during forming and annealing. They help manufacturers produce reliable, safe containers that protect food, beverages and pharmaceuticals.

Want to understand how temperature affects product quality across other critical environments?
Read more about our temperature mapping services.
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