Counter Pressure Filling
& Seaming for Canned Beverages
What is Counter Pressure Filling?
Introduction
Counter-pressure (also called isobaric) filling is a closed, pressure-balanced method used to package carbonated beverages while minimizing oxygen pickup and product loss. It is the standard method used by large beverage producers to package carbonated liquids because it reduces waste and allows precise control over the atmosphere (think carbonation "fizz") inside the can during the fill process. Ultimately, it comes down to the quality of what’s in the can. Whether you’re packaging beer, RTDs, non-alcohol beverages, coffee, or other products, mouthfeel and shelf life are directly influenced by how the beverage is handled at fill and seam.
For craft producers, counter-pressure was historically harder to access at small scale. Today, scaled-down systems make it achievable without giving up the quality fundamentals that matter most: oxygen control, stable carbonation, consistent fill levels, and seam integrity.
This page covers the “why” and “how” of counter-pressure filling, plus how filling and seaming fit into a complete packaging line. If you already know you need equipment, you can also jump to an overview of Codi’s filling and seaming offerings below.
Basics
Counter-pressure filling uses a controlled sequence of purge, pressurize, fill, and pressure-release steps so liquid enters the can under stable pressure conditions—rather than being exposed to ambient air.
In practice, that means:
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The can is sealed from outside air during critical parts of the cycle
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Ambient air can be purged (commonly with CO₂ for beer)
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The can is pressurized to match tank pressure so carbonation stays in solution
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Fill rate and pressure release can be managed to reduce foaming and product loss
The main alternative is gravity (open atmosphere) filling. Gravity filling is common at smaller scales because it’s simple and widely available, but it is limited in the carbonation level that can be packaged in the can, it exposes liquid to air during the fill process and relies heavily on head pressure, temperature, and operator workarounds to manage foam and fill consistency.
Why Counter-Pressure Matters
for Canned Beverages
When you package any carbonated beverage, you are not just moving liquid into a container—you are managing gas, oxygen exposure, and the conditions that determine shelf life.
Lower Oxygen Pickup (DO) and Better Shelf Stability
Oxygen exposure during packaging can degrade aroma, flavor, color, and overall shelf stability. In beverage packaging, oxygen is typically measured in two ways: dissolved oxygen (DO), which is oxygen dissolved directly in the liquid, and total packaged oxygen (TPO), which includes both dissolved oxygen and oxygen trapped in the container headspace after sealing.
Counter-pressure filling is designed to minimize both DO and TPO. By isolating the container from ambient air, purging with a product-stable gas such as CO₂ or nitrogen, and maintaining pressure equilibrium during filling, the process limits oxygen ingress at the most critical stages. The result is more consistent oxygen control, improved flavor stability, and longer shelf life—particularly important for carbonated beverages like beer or wine or any other beverage prone to oxidation.
Carbonation Stays Where You Intended
Reduced Product Loss from Foam and Overfill
CO₂ solubility depends on pressure. When pressure stays stable from tank to can, carbonation is less likely to break out of solution prematurely. That typically means more consistent fills and fewer foam-related issues downstream.
Foam is not the enemy; uncontrolled foam is. With counter pressure, operators can tune agitation and pressure release to build the foam behavior they want—without turning the filler into a “product loss machine.”
Product loss is often highest during line startup, particularly after CIP and sanitization cycles or when packaging in warm ambient environments. Heated product lines, elevated liquid temperatures, and residual gases can increase foaming and instability during the first several minutes of production. In atmospheric filling systems, this frequently results in excessive overflow, inconsistent fill levels, and discarded containers until stable conditions are reached.
Counter-pressure filling significantly reduces these startup losses. By maintaining pressure equilibrium between the product, container, and filling environment, counter-pressure systems suppress foam formation even when temperature and carbonation conditions are not yet ideal. This allows usable product to be filled sooner after CIP or sanitation and reduces the volume of product lost during ramp-up.
The same advantages apply in less-than-ideal operating conditions, including warm cellars, summer packaging environments, or products filled at higher temperatures. In these scenarios, counter-pressure fillers consistently outperform atmospheric fillers by maintaining fill stability, improving repeatability, and minimizing wasted product—delivering better yield and more predictable production runs.
Counter-Pressure Filling Beer
Beer benefits greatly from counter-pressure filling.
In the real world, beer packaging outcomes usually hinge on three operational variables:
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Fill level consistency
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Foam quality/amount
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Speed
When teams begin a run “red-lined” for speed before fill levels and foam behavior have stabilized, issues often surface downstream rather than at startup. Low fills, seam variability, and inconsistent packages become more likely, undermining both product quality and overall line efficiency.
A more reliable approach is to treat speed as the final optimization step. By first establishing stable foam control and repeatable fill levels, producers can then increase throughput with confidence—protecting package integrity, reducing rework, and delivering a more consistent product to market.
Fill Levels and Headspace
Consistent fill levels are easier to achieve when the filling process is stable. Product temperature, tank pressure, fill parameters, and controlled pressure release all directly influence foam behavior and repeatability.
In beer packaging, best practice is to cap on foam. A controlled foam cap displaces oxygen from the can immediately prior to seaming, minimizing total packaged oxygen (TPO) and protecting flavor stability. Rather than relying on a fixed, air-filled headspace, counter-pressure filling enables repeatable foam generation and collapse, allowing precise liquid volumes while maintaining oxygen control.
When these conditions are properly managed, producers can achieve uniform fills, reliable seams, and low oxygen pickup—creating a stable foundation before increasing line speed.
A tight, stable foam cap before seaming can help protect the product by discouraging oxygen ingress. Foam behavior changes with product conditions (carb level, temperature, recipe variables) and environmental conditions (ambient temperature, pack hall variability). Operators get the best outcomes when they let the product “tell them what it needs,” then adjust run parameters accordingly.
Foam Quality and DO Control
Speed After Stability
In packaging, “fast” is not always efficient. A stable run at a slightly lower speed often yields higher net throughput because it allows cans - even under less-than-ideal conditions - to be filled correctly. The goal is controlled repeatability, then velocity.
When Counter Pressure is Required
(and when it is not)
Counter-pressure is strongly indicated when you are dealing with:
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Carbonated beverages with CO₂ volumes above 2.7 vols (many seltzers, sparkling wine, and sodas)
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Quality targets that require lower dissolved oxygen
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Facilities where maintaining very low fill temperatures is challenging can benefit significantly from counter-pressure filling. When a bright tank is located some distance from the filler, product temperature can increase as the liquid travels through transfer lines that are exposed to ambient air. Even modest temperature rise can increase CO₂ breakout and foaming at the filler, making stable fills more difficult—particularly with atmospheric systems.
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Whenever product loss (particularly at startup) is not acceptable.
Gravity/open atmosphere filling can be workable for:
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Still products (where carbonation management is irrelevant)
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Small runs where shelf life and DO targets are less demanding
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Cases where process constraints are simple and consistent (and expectations are aligned)
Filling and Seaming as a System
(Not Separate Machines)
An inline canning system performs two primary functions: filling the container and sealing it—typically by seaming, or in some applications, capping. These functions are inseparable. A poorly seamed can will negate even the most precise and well-controlled fill.
Even with a good fill, oxygen pickup can occur in the short window between filling and seaming if timing, lid drop, and foam control are not tightly managed.
For that reason, canning must be treated as a holistic operation. Fill consistency, foam behavior, pressure release, and transfer timing must be coordinated with lid placement and seamer performance. A tightly controlled transition from fill to seam is essential to minimizing oxygen ingress, protecting product quality, and delivering consistent, shippable packages.
The Importance of a Quality Seam
Seaming is a two-operation process: the first operation forms the seam geometry; the second consolidates it. Consistency matters, and routine seam checks are the difference between quiet confidence and a painful surprise after product has already left the building.
Timing Between Fill and Seam Matters
Once the can leaves the fill heads, it is in the “handoff zone.” The longer that handoff takes, the more opportunity there is for foam collapse and oxygen exposure. Seamer speed and conveyance design should be aligned so the line supports the quality objective, not just throughput.
Pre- & Post-Canning Line
Equipment Considerations
Most canning lines—regardless of scale—are variations of the same core flow:
Depalletize → Clean → Fill → Seam → Rinse or Pasteurize → Dry → Label (if not preprinted) → Pack (carrier or carton) → Palletize
A few pieces of “support” equipment often make an outsized difference.
Pre-Fill Machines
Pre-fill operations prepare empty containers for consistent, hygienic filling and reliable downstream performance. These systems establish the starting conditions for the entire packaging line.
Depalletizers automate the handling of empty cans, delivering them to the line at a controlled rate while reducing manual handling and the risk of damage or disruption.
Container cleaning or rinsing systems remove dust, debris, and residual contaminants from empty cans before filling. Clean containers support product integrity and help prevent downstream issues related to foaming, sealing, or label adhesion.
Post-Fill Equipment
Post-fill operations enhance filled cans into finished, shippable packages.
Post-seam rinsing removes residual product from the exterior of the can and helps maintain clean operating conditions. Warmers or tunnel pasteurizers may be used to manage condensation, stabilize the package, or extend shelf life depending on product type and distribution requirements. Drying systems prepare cans for labeling or secondary packaging by ensuring surfaces are clean and dry.
When cans are not preprinted, a label applicator applies the label to the container, transforming a bright can into a branded package. Carrier or carton applicators then group cans into retail-ready packages.
Across post-fill operations, conveyance and accumulation connect each process and allow the line to absorb normal variation without repeated stoppages. Proper integration from seaming through palletizing is essential to maintaining throughput and consistency.
Codi's Filling & Seaming Machinery
Codi brought the first inline counter-pressure filler to market in 2015. As customers adopted the platform and pushed it into real production environments, many began asking for additional upstream and downstream equipment—starting with depalletizers—to better support the overall packaging process.
In response, CODI Manufacturing expanded its scope, applying the same engineering discipline and manufacturing expertise to deliver complete pre- and post-fill solutions. The objective was not simply to add equipment, but to ensure the entire packaging line operated as a cohesive, well-integrated system.
As our founder put it, “we were determined to do it better.”
Counter Pressure Filling & Seaming Machinery
Story: Around a decade ago, when we first committed to making a canning machine, "we decided to make ours with stainless-steel instead of the aluminum and plastic our competitors used."
"Everyone told us we were crazy, but suddenly we built a canning system that was easier to CIP and it was a true counterpressure machine. Importantly, our customers could fill a wider range of products., high-carb, hot-fill, you name it."
"We were determined to do it better."
Counterpressure Filler/Seamer
CCL-45
The Codi CCL-45 fills and seams cans quickly and precisely at high carbonation levels (or elevated temperatures) that atmospheric fillers can't handle. True clean-in-place (CIP) technology eliminates microbial contamination and minimizes water and chemical consumption through a self-contained recirculation system. This is a solidly-built automated inline machine for beverage producers requiring consistency, hygiene, and years of service.
CE Counterpressure Filler/Seamer
CCL-45CE
The Codi CE Monoblock is engineered for EU compliance while delivering the same precise, high-speed counterpressure filling and seaming performance as the CCL-45. It handles high carbonation and/or elevated product temperatures that atmospheric fillers can’t. Its clean-in-place (CIP) system prevents microbial contamination, and its low dissolved-oxygen fills help extend beverage shelf life. The CE Monoblock is a dependable choice for producers who demand quality from their equipment and in the beverages they package.
ROPP Filler/Capper
CCL-45ROPP
The Codi ROPP system provides flexible filling for both aluminum cans and recloseable ROPP bottles, allowing producers to package a wide range of beverages. Compatible with ROPP cappers from Zalkin, NP-RC, Zonesun, Arol, and Tecno Max, the CCL-45ROPP delivers consistent fills, sanitary clean-in-place performance, and adaptability for both commercial and craft beverage operations.
Specialty Seamer
Meadow
Codi Manufacturing is the exclusive equipment partner for building seamers specifically designed for the MEADOW KAPSUL™ can-end application developed by Meadow Global. Codi values our partnership with Meadow Global and is excited to bring new technologies to the canning industry. Please reach out to us to learn more about Meadow or to order a Meadow Seamer.
