What causes cans to leak during production and how should we investigate the root cause with our co-packer?

Leaking cans are caused by multiple factors and rarely point to a single culprit. A full technical investigation is needed, as the seal itself is usually tested rigorously during production.

**Common root causes members identified:** - **Exterior corrosion from low-pH products** — The outside of the can lacks the internal plastic coating protection. In acidic drinks (RTDs, ciders, low-pH beverages), the product can eat through the exterior over 6+ months, typically leaking from the top or bottom seams where water spray protection was not applied before labelling. - **Can specification or liner changes** — If the co-packer has changed the can spec, can lining, or the liner material, this can introduce compatibility issues with your product. - **Recipe or ingredient alteration** — Even minor tweaks or ingredient changes affecting acidity can trigger leaks; verify target pH levels with your recipe team. - **Production pressures or corner-cutting** — Members noted leaks occurring during can shortages (e.g. late 2023/early 2024) when manufacturing standards may have been compromised. - **First-run production** — New SKUs run for the first time carry higher risk if pre-production testing was incomplete.

**Investigation approach:** - Request a full technical incident report from the co-packer documenting can supplier, liner material, production dates, and any process deviations. - Engage your can supplier, recipe/product team, and co-packer to rule out each variable systematically — each party often blames the others. - Check whether the issue affects all SKUs or just specific ones (some members saw leaks on 1 of 3 SKUs). - Document cascade failures: one leaked can can contaminate multiple cans below it in stacked pallets ("Christmas tree effect").

**Caveat:** Root cause may remain unclear even after investigation, as responsibility is often disputed across multiple parties. Members recommend proactive dialogue with your co-packer early and involvement of experienced operations staff to document findings.