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Within the beverage industry, we hear a lot of confusion about the difference between batch and tunnel pasteurization. So, we interviewed one of our experts to help clarify.

Read on to discover our sit-down discussion with Chris Todorow, Descon’s Application Engineer.

What is a Batch Pasteurizer vs a Tunnel Pasteurizer?

The process of pasteurization itself is the same regardless of whether we’re talking about batch pasteurization or tunnel pasteurization.

When we think about pasteurization, we think of small runs, slow filler rates, small production, and low-volume type of applications.

Where we see a lot of confusion with our customers is they’ll think of batches, but they’ll think of them in very high volume scenarios.

So if you’re talking about a batch, but you’re talking about hundreds of hectoliters at a high filler rate.

Even though you might consider that a batch, it’s at such a line rate that you need a tunnel pasteurizer regardless of whether you’re running batches or not.

You also get to a certain point where you just can’t keep up manually packaging at fast line rates.

What are the Main Differences Between Batch Pasteurizers and Tunnel Pasteurizers?

Batch Pasteurizer 

• Hand filled and labour-intensive
• Slower and smaller production volume
• Designed for smaller companies

Tunnel Pasteurizer 

• Supports continuous production
• Energy-efficient due to its regenerative heat load
• Reduces the heat load on the machine by as much as 50%
• Lower gas and steam consumption
• ​​Significant increase in utility savings
• Higher production volume

What Types of Companies Require Pasteurization?

At Descon, we’ve had some businesses from small wineries and small brewhouses that run many different flavours, but in different batches, small volume batches. These are the type of customers that we see utilizing batch pasteurizers effectively.

As soon as you start getting into the higher volume or higher filler speeds, or a lot of batch runs, it becomes more effective and efficient to go with a tunnel pasteurizer.

When you go with a tunnel pasteurizer you generally also need a lot of peripheral equipment, such as steam, packaging, and inspection equipment.  Therefore, these systems can be a large investment for our customers. And if we’re talking about craft breweries, they don’t always have that type of investment.

What is the Labour Commitment for Batch Pasteurization?

Labour demands depend on how quickly a client wants to run through the process. For example, you can do it with one to two people, but it would just be a slower process. As our machine is capable of being loaded on both sides you could use 4 people to load the machine quickly and reduce the cycle time.

In simple terms, batch pasteurization requires loading the machine with crates of product and then running the machine through a pasteurization process and then unloading the crates.

What is the Labour Commitment for Tunnel Pasteurization?

​​With the tunnel pasteurizer, you have a filler and you have a conveyor system that feeds directly from the filler into the pasteurizer. With the tunnel, your filler automatically runs through the process as long as the filler is running. You then have more conveyor that discharges the pasteurizer then into downstream packaging equipment.

In other words, this pasteurization process is completely automated.

How do Companies Pick the Right Pasteurization Solution?

At Descon, we have preliminary documents that we sent to clients so that they can fill out specific product details. We ask for some information about the process, what product they’re trying to run, as well as the available utilities required.

Apart from that, our team conducts an initial conversation with prospective clients to help them fill out the application and give suggestions on where our product line fits.

What is the Start-Up Time Required for Implementing Pasteurization Solutions?

Our batch pasteurizer is a self-sufficient unit that gets shipped pre-assembled. Large tunnel pasteurizers come shipped in sections on flatbeds and then we reassemble them on-site, smaller machines can be shipped in one piece.

Therefore, it can be more involved to assemble larger tunnel pasteurizers.

Is Pasteurization Bad for the Environment?

With the batch pasteurizer, the customer has an option for the two storage tanks, the hot and the cold tanks. We specifically supply storage tanks as it is a more energy-efficient use of the process water.

If we don’t supply storage tanks, we use cold city water to drain. Therefore, as far as water conservation is concerned, using storage tanks is a best practice.

At Descon, we try to push our customers towards using these storage tanks as well as auxiliary cooling, because that’s more efficient than using a cold city water source.

As a bonus, if they have a water tower, that’s even better, because it’s the most efficient method of forced cooling.

We try to utilize every efficiency we can as far as the conservation of utilities.

What Beverage Products can be Pasteurized?

Generally speaking, our pasteurization solutions work for any filled container. However, milk is a completely separate process from a lot of other pasteurizer processes.

At Descon, we only offer post-filler pasteurization solutions. We generally deal with soft drinks, beers, ciders, and RTDs.  We can also provide solutions for wine coolers and CBD-infused beverages. Currently, we do not provide pasteurization solutions for milk products.

Why Doesn’t Descon Pasteurize Milk?

Milk requires very high-temperature pasteurization using flash pasteurization. In other words, the milk industry hits their product with a lot of heat, really quickly, for a very short period before filling.

In the beverage and brewery industry, you want the opposite. Our clients want to see the lowest possible temperature in pasteurization for the longest period because it has the least effect on flavour and taste. This is done after the filling process.

What Happens During Pasteurization?

Anything above 140°F is considered pasteurization temperature, or 60°C. At this temperature, the heat is killing bacteria that are naturally in the organic product that’s inside the beverage. The longer you pasteurize the more bacteria is destroyed.

That’s why organic products tend to need higher pasteurization because there’s a higher bacteria content.

Depending on the type of product, whether it’s acidic or basic, you might have to hit a higher temperature.

If the product is basic, like milk, you can kill the bacteria, but you can’t stop the spores from germinating into bacteria. Therefore, you must hit milk with a lot higher temperature to kill the spores as well as the bacteria.

In an acidic beverage, the spores can’t germinate into bacteria because of the acidity of the liquid. So the high temperatures required to stop spores from germinating are not required.

Does Every Beverage Company Need Pasteurization?

The short answer is no.

You can safely drink a new product that’s not pasteurized because the bacteria haven’t germinated enough to make you sick. However, the shelf life, the amount of germination time it needs to make you sick, is a lot shorter because you haven’t killed any of the bacteria before you put it on the shelf.

Can Pasteurization Extend Shelf Life Forever?

No matter what type of pasteurization you do, you’re never going to completely sterilize the product with pasteurization. So, there will always be a limit to the shelf life, regardless of how many pasteurization units you can build.

Are there Mandates for Pasteurization in Canada?

As far as milk is concerned, pasteurization is mandated by federal regulations.

For the products we pasteurize at Descon, requirements are regulated through governing bodies such as the LCBO. In Ontario, the LCBO has created best practices and suggestions for products requiring pasteurization.

While the LCBO doesn’t require you to pasteurize your product, most beverage manufacturers choose to pasteurize to prevent the risk of financial loss due to spoiled products.

What Kind of Steam Does a Pasteurization System Require?

There are a lot of different systems you can supply for steam. Generally, we’ve done a lot of steam boilers and we supply those steam boilers and integrate them into our equipment.

More recently, we have moved toward direct fire gas heaters, because they have higher efficiency. And in a lot of regions, our clients can access credits from their local ministries for improving efficiency.

We’re also getting some inquiries about steam generators because there can be advantages to using steam generators instead of a boiler, depending on regional regulations.

While there are advantages and disadvantages to all three main types of solutions, we work with our clients to find the best solution for their needs.

How Many Pasteurization Units are Needed?

Generally speaking, we refer our clients to our go-to experts in the US and Canada who perform biological testing to determine the type of bacteria as well as its natural concentration level in the product.

Once this level has been identified, we can figure out how many pasteurization units our clients will need and at what specific temperature to get to the required shelf life.

What is the Best Piece of Advice for those Purchasing Pasteurization Solutions?

We always try to push the customers to look for future production throughput. If they want to run faster in the future, it is wise to buy a larger machine now and run it slower temporarily. Then, in the future, they can increase filler speed.

Ultimately, the investment is better to do it initially.

About the Expert

Connect with Chris on LinkedIn.