Oct 27, 2026Functional & Specialty Packaging
Spout Pouch Leakage: 4 Failure Points and One Test
Four places a spout pouch leaks, the three causes we see most often, and the one test that catches them before mass production.
Where Spout Pouch Leakage Starts
A spout pouch rarely leaks because of one bad decision. It leaks at the weakest of four joints, and which one is weakest depends on your formula.
The four points
- Spout-to-film seal — the join most often at fault, and the one that responds least to a heavier film
- Side and bottom seals — affected by fill temperature, and by how much product sits in the seal area while filling
- Cap and spout thread — leaks here look like pouch failures but are usually closure fit
- Film pinholes — from handling, or from a structure too thin for the fill weight
Three causes we see most often
Testing with water instead of product. Water passes a seal that a surfactant-rich shampoo will find. Test with the actual formula, or the closest representative one.
Filling too hot or too full. Both put stress on the seal area during filling, and the failure shows up days later in the carton rather than on the line.
A spout chosen for price rather than for the nozzle. A bore that is too small forces pressure at the fill head, and the seal takes it.
The test worth doing
Fill a sample with your product, leave it, then drop it and compress it in a carton. A pouch that survives a week standing upright is not evidence. A pouch that survives a carton drop is.
For a new project we recommend approving a filled sample before mass production, and we run leak and seal checks on every batch.
Related guides
Next step
Send the product, fill volume, viscosity and filling method — those four decide where the risk sits, and what we would test first.
