The Art and Science of Canning: Atmospheric vs Counterpressure Filling

Beverage producers are faced with many questions when deciding how to can their products. Everything from the can-lining to the can design is important, but no decision is more expensive (in the short term) than deciding which can-filling machine to buy.

We wish we could say it’s a simple decision, but there are several factors at play that go into deciding between atmospheric and counterpressure machines. Not only do you need to know the size machine that’s right for your business at each stage, you’ve got to determine which type of fill method works for your products. 

In this article we’ll explore what makes each machine unique, what types of beverages are best for each one, and which machines fit for different company sizes. As you read, if you have questions about your specific company’s needs, feel free to reach out to a member of our sales team here: sales@americancanning.com or give us a call 512.931.1226.

Atmospheric Can Filling

Atmospheric filling machines work by using CO2 to push liquid into open containers under normal atmospheric conditions. A combination of valves and flow restrictors balance the flow rate and depressurization rate. This allows users to fill without excess foam and breakout, that ultimately result in low-fills and product loss.

Atmospheric machines don’t seal the container until after the can is filled so internal pressure can’t be changed during filling. This means that an atmospheric machine works best when product temperature and carbonation are easily controlled.

The simplicity of this type of filling system has its limitations, but it also has significant benefits. Namely, speed. Atmospheric filling machines work much faster per fill head than counterpressure machines and typically use less gas, compressed air, electricity, and water.

The primary risk of atmospheric filling is product waste due to the limited control in the filling cycle. An experienced operator will cut down on these issues, but for those less experienced, the learning curve can be steep. Atmospheric filling machines typically lack precise digital controls so becoming a great operator often requires a “feel” for the machine that is developed through repetition. This can lead to a long period of training and significant product waste, especially at the beginning.

As those in the industry often say, there is both art and science involved in the brewing process. Packaging is much the same. An atmospheric machine is often better for operators who fashions themselves as artisans versus those who desire the precision of a scientist. 

It’s common for producers to start with an atmospheric machine, and move to a counterpressure machine as they grow and precision becomes vital.

Atmospheric fillers often have a higher initial start-up cost, however they are generally more affordable to purchase than comparatively-sized counterpressure machines.

Counterpressure Machines

Counterpressure filling machines create a pressurized environment within the container before filling. This pressurized environment is typically created using an inert gas, such as carbon dioxide or nitrogen.

A seal is created during filling to control the pressure inside the can, thus substantially improving the fill control, and preventing the carbonation from breaking out the of the can. For beverages that are prone to excessive foaming and breakout, a counterpressure machine saves significant product waste.

A counterpressure machine is very flexible, pretty much all liquids work well with these machines. However, due to the fact that each container must be sealed, pressurized, and depressurized in addition to the filling, a counterpressure machine is slower than an atmospheric machine of a comparable size.

Counterpressure machines are much more precise than atmospheric machines, but the digital controls can be challenging to master. Often a counterpressure machine is more complicated to learn and master than an atmospheric machine. While atmospheric machines come down to the “feel” that the operator learns for the machine, a counterpressure machine’s controls might be overwhelming for operators with non-technical backgrounds, requiring extensive training and study of the controls. 

While the atmospheric machine is for the “artisan” who appreciates the art of beverage canning, the counterpressure machine is designed for the “scientist” who wants to tightly control every factor.

Comparing the Machines

Here’s a quick breakdown of the most common metrics that differentiate atmospheric and counterpressure filling machines:

The easiest way to sum it up is that atmospheric filling = speed. Counterpressure filling = flexibility and control.

American Canning’s Solutions for Common Challenges for Each Machine

American Canning strives to make every machine compact, easy-to-use, and efficient for our customers. Whether that’s the entry-level AT-1 or the powerful AT-6 atmospheric machines, or the CP-4 counterpressure filler, American Canning is aware of the challenges these different fill methods present to end operators. 

We’ve worked hard to develop canning machines that limit challenges for customers so user can be confident in their ability to package products effectively without wasting time or product.

Atmospheric

No matter what, every atmospheric machine can have issues with product loss. That’s just part-and-parcel of the fill method. American Canning’s atmospheric machines have specific features to help address these challenges. Each of our atmospheric machines come with highly refined fill-head flow characteristics, discrete control of the flow restrictors, and a simplified digital operator interface. These features make mastering our atmospheric fillers easier, limiting time spent by the operator learning the “feel” of the machine.

Counterpressure

Traditionally, many smaller breweries have shied away from counterpressure machines due to complicated interfaces. Often they’d rather go with an atmospheric filler and deal with the lack of precision instead of the daunting nature of learning counterpressure machines.

Knowing that, American Canning’s counterpressure machine, the CP-4, was developed to be one of the simplest machines on the market to learn. We made the digital interface as user-friendly and repeatable as possible, significantly shortening the learning curve and giving even the smallest beverage producers access to this fill method. 

The AT-6 might sound a little intimidating at first. With its ability to fill more than 60 cans per minute and its elevated sticker price, you might feel that the AT-6 is beyond your brewery’s current needs. Maybe that’s true, but it might be worth a closer look.

Due to its dual line capability, the AT-6 is actually the perfect machine to be with your brewery as you scale.

Say you currently fill 20-30 cans per minute, but you have plans to scale to 60 cans per minute within the next few years. You might be tempted to purchase a smaller machine instead of investing in more fill-heads, but in the long run you’ll end up purchasing two machines instead of just one. This costs not only money for the new machine, but implementation costs, employee hours, production disruptions, and having to navigate financing more than once. Combined, those potentially delay your ability to scale as quickly as needed.

The AT-6 is also compact, meaning that it takes up less floor space than most comparable machines.Your space doesn’t have to expand in order for your supply to scale and meet demand.

Invest in the Best Fit

Both atmospheric and counterpressure are great options for beverage producers, but choosing the correct one for the level that your company is at is key. Purchasing with scale in mind is important however it’s equally important to not over-invest in a machine that’s too much for your business needs.

All American Canning machines are designed to be modular with infeed and out feed equipment. So consider that in addition to fill method. 

If you’re interested in a great counterpressure machine, our CP-4 is the perfect option for a beverage producer seeking flexibility. For the rapidly scaling brewery, the AT-6 is the machine that can take your brewery to the next level. Or for those just looking to get started and gain independence in can packaging, the AT-1 single head filler is a fantastic first machine.

Our machine sales team can work with you to make sure that you purchase the best machine for your company. Reach out here sales@americancanning.com or give us a call today 512.355.0089.