Tunnel Pasteurization: What to Know

Pasteurizing beverages helps extend their shelf life while making sure they’re safe for consumption once they hit the shelves. Tunnel pasteurization is one way to handle this process, and it can be particularly effective for carbonated beverages.

The advantages that tunnel pasteurization of carbonated beverages offers food processing companies, breweries, and other industries stem from the way its process works.

Tunnel Pasteurization Process

Tunnel pasteurization is unlike other pasteurization processes in that it gradually treats products in a continuous flow from one end of the system to the other rather than shooting for a single target temperature in one go.

• Gradual heating

The bottled or canned product passes into the tunnel through one end, and throughout the tunnel, its temperature is raised with sprays of hot water. The temperature is brought up in stages.

In each stage, the product and container are brought to a target temperature and held there long enough to kill off specific microorganisms. After that, it’s conveyed to the next stage, where the temperature is brought up a bit higher, held in place, and so on until it reaches the maximum desired temperature.

• Cooldown

After reaching the maximum temperature desired, the product is gradually brought down to room temperature. The entire concept is incremental temperature changes instead of bringing the product up to the top temperature in one blast.

• Palletization and shipment

After the product is brought back down to room temperature, it’s ready for labeling, boxing, and palletization.

Advantages of Carbonated Beverage Tunnel Pasteurization

Tunnel pasteurization offers numerous benefits to breweries, food processing facilities, and anyone else who produces carbonated beverages.

• Compatibility

First off, tunnel pasteurization is compatible with most carbonated beverages. Some pasteurization methods, such as hot filling, don’t allow for CO2 to be added to the beverage since it causes too much foaming during the process.

Tunnel pasteurization, on the other hand, enables certain amounts of CO2 to be present in the beverage. While there are limits on how much the process can handle, it does offer an advantage over methods that don’t allow for it at all.

• Prevents over-carbonation

In addition to being safe for certain levels of carbonation, tunnel pasteurization can be helpful when it comes to preventing over-carbonation.

For instance, some microorganisms found in beer may produce excess CO2, causing the beverage to burst out upon opening. Tunnel pasteurization prevents that from happening by eliminating those microbes.

• Prolongs shelf life

Pasteurization extends the shelf life of carbonated beverages by removing microbes that cause them to ferment or deteriorate in other ways. This is especially important in beverages such as sodas which have high amounts of sugar.

Prolonging the shelf life of these beverages is vital since there may be a long period between production and final consumption by the consumer. They may sit on shelves for weeks or months, endure lengthy travel, and may spend some time in a refrigerator or cupboard after purchase. To ensure they remain fresh, pasteurization is an absolute must.

• Preserves packaging

Another advantage of tunnel pasteurization is that it can be used on products that are in fragile packaging, such as glass bottles or aluminum cans. Sudden changes in temperature can affect these materials in destructive ways, causing glass to shatter and aluminum cans to burst, especially when there’s heated product inside.

By handling the pasteurization process gradually, these types of packaging don’t have to endure the kind of temperature shock that they might go through in other processes, such as flash pasteurization. The result is a more reliable pasteurization process that can withstand continuous flows of packaged carbonated beverages.

Using Tunnel Pasteurization in Your Facility

Tunnel pasteurization has its advantages, but to be truly effective, it needs to be used properly.

• When to use tunnel pasteurization of carbonated beverages

Tunnel pasteurization can be an effective way to handle mass-produced beverages. Since they’re produced and bottled in a continuous process, adding a tunnel pasteurizer to the production line to manage a constant line of product makes sense. Product can be pasteurized without halting the production line to add or remove batches.

• Keep in mind the cost

In general, tunnel pasteurizers tend to cost more than hot-fill systems, which means they’ll typically be best used in production lines that would benefit from the cost-savings of a continuous process.

On the other hand, if the product is typically made in batches, then tunnel pasteurization likely wouldn’t be worth the cost.

• Fine-tune your equipment

If it’s not properly implemented and calibrated, a tunnel pasteurizer can lead to some of the same problems any production line might cause, including inconsistent quality and negative impacts on flavor. As such, it’s important to have your system built by trusted industry experts.

One point to keep in mind here for carbonated beverages is there are limits to how much CO2 you should introduce into the product before pasteurization. Too much, and it could cause problems, so make sure your system is right for what you’re producing.

• Design by professionals

If you’re considering implementing a tunnel pasteurizer in your carbonated beverage production process, you’ll want to get seasoned professionals to design and build the system for you. The temperature levels and timing of the system has to be right for the beverages you’re producing while also matching your production line’s flow, so nothing short of reliable designers and fabricators should be trusted for this process.