The secret to the foam in the interior coatings Explaining how the Draft Beer Can Foams

Can coatings of TOYOCHEM, which brings together artience group's polymer design technology, boasts the top market share in Japan. We have a long track record as an interior coartings for canned beer and are highly trusted.
In 2021, Asahi Breweries Co., Ltd. released the "Asahi Super Dry Draft Beer Can," which became a social phenomenon. TOYOCHEM took on the challenge of developing the interior coatings, which was key to this success, together with Asahi Breweries. The moment you open the lid, fine bubbles rise, allowing you to enjoy the deliciousness of a draft beer anywhere you want at a shop——。 Behind this moving experience was our "Draft Beer Can coatings," which broke conventional conventions and was born through joint development. Here, we introduce the mechanism of this revolutionary coatings.

• The Role of Canned Beer Interior Coatings
• The secret behind the foaming in the Draft Beer Can
• Value co-creation with customers that breaks conventional wisdom

The Role of Canned Beer Interior Coatings

The inside of beverage and food cans is coated with coatings for the following purposes:

• Protects the can from its contents (corrosion prevention)
• Protecting the flavor of the contents and consumer safety (preventing the leaching of metal components in the can)

One of the values our can beer interior coatings have provided for many years is "suppressing foam formation when opening cans." In traditional canned beer, foam spraying out when opening was never allowed because it could stain consumers' clothing or homes. Based on numerous past failures, our company researched methods to suppress foaming and clarified that uneven surfaces in the interior coatings surface cause foaming. Since then, we have accumulated coating technology capable of forming smooth coated surfaces.

The secret behind the foaming in the Draft Beer Can

The key to the coatings for the Draft Beer Can lies in its "micro-textured surface," that overturns the concept of ordinary interior coatings. This was made possible by the polymer design and formulation technology we have cultivated over many years. By utilizing the heat from the drying process after coating, micron-level crater structures are created on the surface of the paint film, forming millions of small unevenness on the inner surface of the can.
Beer contains a lot of carbon dioxide dissolved in the first place. Carbon dioxide is stimulated when liquids shake violently or touch rough protrusions, appearing as gas (bubbles). Typically, bottled or canned beer foams from the impact when poured into a glass, while draft beer foams as it passes through the spout of a beer server. The Draft Beer Can utilizes this property: the moment the lid is opened, internal pressure is released, and each of the millions of bumps becomes the starting point for the bubbles, allowing fine bubbles to continuously rise.

(1) Assumption Mechanism for Beer Foaming

(2) Microscopic Observation Image of the Inside of the Can

Upon observation under an electron microscope, you can see that the inside of the Asahi Super Dry Draft Beer Can has small, sparse crater-like unevenness. Also, when observed with a confocal laser microscope, you can see that these unevenness have heights.

Electron microscope image of the inside of the Asahi Super Dry standard can

Electron microscope image of the inside of Asahi Super Dry "Draft Beer Can"

Confocal laser microscope observation image of the inside of Asahi Super Dry "Draft Beer Can"

(3) Beer foam test

Value co-creation with customers that breaks conventional wisdom

The idea proposed at the exchange meeting between Asahi Breweries and our technical department—"canned beer that foams the moment you open the lid"—was the complete opposite of conventional wisdom. The inspiration for development came from our past failure story where "canned beer foam would erupt." Our technology, which identified and controlled phenomena that were originally considered "quality failures," combined with Asahi Breweries' passion to "delivering the excitement of enjoying a draft beer just like at a bar anywhere," led us to jointly develop coatings to take on the challenge.

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Voices from Asahi Breweries Developers

─In order to provide this "Draft Beer Can coatings," we spoke to Mr. Ryuhei Kuroda and Mr. Hiroaki Nakajima of the Packaging Technology Research Institute of Asahi Breweries Co., Ltd., who were involved in the development.
Usually, the development of beverage cans was carried out only with the can manufacturer. 
Normally, when it comes to internal coating properties, we are indirectly involved through the can manufacturer, so it was an unusual case that we worked directly with can coating manufacturer TOYOCHEM.
Our joint development was a combination of various coincidences, but looking back, I feel that it was a very fruitful project.
TOYOCHEM was quick to respond, willingly accommodating requests for improvements just before testing the actual machine, and had a wealth of scientific knowledge, making for a truly fulfilling technical exchange.
Asahi Breweries, which has delivered deliciousness that exceeds expectations to customers through two approaches: evolving the contents of the beverage and its aluminum packaging aluminum. From this co-development, we have acquired a new approach called interior coating.  By continuing to refine this partnership, we hope to deliver even more "delicious!"

Through years of product development, our company has accumulated unique technologies. This time, we sincerely addressed the requests of customers with different perspectives and were able to create value unlike anything we had seen before. Going forward, we will continue to provide value that resonates with the senses that move people's hearts—surprise, excitement, and comfort—together with our customers.