When you receive a shipment of custom-printed stand up pouches, the design and color are usually the first things you notice. However, the most critical feature isn’t visible to the naked eye: sealing integrity. A single leak can lead to product spoilage, messy shipping disasters, and damaged brand reputation.
At Lebei, we use professional laboratory equipment to ensure every batch is secure. But even if you aren’t at a factory, you can perform these three simple tests in your office or warehouse to verify if your pouches are truly leak-proof.
The Squeeze Test (Pressure Resistance)
This is the quickest way to check the strength of the side and bottom seals.
- How to do it: Fill the pouch with air and seal it tightly using a heat sealer or the built-in zipper. Lay the pouch on a flat surface and apply firm, steady pressure with both hands.
- What to look for: The pouch should feel firm like a balloon. If you hear a faint hissing sound or feel the air slowly escaping, the seal is compromised. Pay close attention to the T-junction where the bottom gusset meets the side seals—this is often the most vulnerable point.
The Inversion and Compression Test (Liquid Leakage)
If you are packaging liquids, oils, or powders, this test is essential for checking the zipper or spout reliability.
- How to do it: Fill the pouch with water (or your actual product) to its recommended capacity. Seal it and turn it upside down. Place a piece of dry paper towel underneath it and leave it for 30 minutes. For a more rigorous test, place a small weight on top of the inverted pouch.
- What to look for: Any dampness on the paper towel indicates a micro-leak. This often happens if the sealing temperature during production wasn’t perfectly calibrated for the material thickness.
The Drop Test (Impact Durability)
Bags are often tossed and stacked during transit. A pouch that looks good on a shelf might burst when dropped from a delivery truck.
- How to do it: Fill the pouch with its intended weight (e.g., 500g of coffee or 1L of liquid). Hold the pouch at waist height (about 1 meter) and let it drop onto a flat, hard floor. Repeat this three times, dropping it on its bottom, side, and face.
- What to look for: Check for any splitting at the seams or punctures in the film. A high-quality pouch with the right laminate structure should easily survive these impacts without losing its seal.
Why Sealing Integrity Matters for Your ROI
Testing isn’t just about avoiding a mess; it’s about protecting your investment. High-quality materials and precise manufacturing ensure that your packaging survives the entire journey from the factory to the consumer’s home. If your current pouches fail any of these tests, it’s time to re-evaluate your material structure or your supplier’s quality control process.
About Lebei: Your Strategic Packaging Partner
Founded in 1995, Lebei is a premier wholesale flexible packaging manufacturer specializing in high-efficiency supply chain solutions. Operating from a 20,000 square meter facility with 150+ experts, we maintain a 2,000,000+ pcs inventory of ready-to-ship plain pouches alongside advanced ODM/OEM services.
Serving brands in 50+ countries, we combine 29 years of industrial expertise with the agility needed for modern batch purchasing. At Lebei, we don’t just print bags; we engineer secure, leak-proof solutions that protect your product and your brand’s reputation.
