QR Codes on Bottles and Cans

How much curve is too much

The usable rule: the code must sit within an arc of roughly 30 degrees of the container's circumference. Beyond that the edge modules turn away from the lens and the decoder gives up.

In practice that means a maximum code width of about:

• 330 ml slim can, 53 mm diameter, gives you about 14 mm of usable width
• 500 ml standard can, 66 mm diameter, gives about 17 mm
• 750 ml wine bottle, 75 mm diameter, gives about 20 mm
• Growler, jar or magnum, 100 mm and up, gives 26 mm and behaves almost like a flat label

Those widths are small, so keep the payload short. A long URL forces a higher QR version with more modules crammed into the same width, and each module gets tinier. A dynamic code with a short redirect is not a convenience here; it is what makes the print physically possible.

Placement on the label

• Put the code on the back or side panel, centred on the vertical axis, so the curvature is symmetrical around it.
• Never let the code cross the label seam. A seam is a step in the surface and it breaks the pattern.
• Keep it away from the shoulder and the taper, where curvature runs in two directions at once.
• Leave a generous quiet zone. On a curve the effective quiet zone shrinks because the outer edge is already turning away.

Material problems specific to drinks

• Metallic and foil labels reflect straight into the camera. Print the code on a matte white panel deliberately placed for it.
• Condensation on a chilled bottle scatters light. Real-world scanning happens on a cold, wet can, so test that way rather than at room temperature.
• Shrink sleeves distort as they conform. Codes must be pre-distorted by the printer or placed on the flattest section.
• Clear-on-glass labels leave the liquid as the background. A dark stout behind a black code is unreadable. Print a white backing panel.

What goes behind the scan

Beverage is one of the categories where the scan genuinely earns its place:

• Tasting notes, pairings and the story of the batch, which is the whole premise of craft
• Batch and traceability data through a GS1 Digital Link, increasingly a compliance requirement rather than a marketing nicety
• Where to buy again, with a store locator or direct reorder, the highest-value link on the label
• Recycling and deposit-return instructions, which regulators in several markets now expect on-pack
• A competition or loyalty entry that turns one purchase into a known customer

Test the way people drink

Scan a cold can from a fridge, held at arm's length, under a kitchen light, with a three-year-old phone. If it reads there, it reads in a bar.