1. Controls Internal Pressure
Milk reacts to temperature changes. As it moves from warm delivery trucks to cold refrigerators—or if it’s accidentally left in freezing conditions—the liquid can expand or contract. The circular dent acts as a flexible pressure point, allowing the jug to adjust safely.
If the jug didn’t have this feature, pressure changes could cause the plastic to warp, crack, or even rupture. In simple terms, the dent works like a built-in pressure release.
2. Helps Prevent Leaks and Breakage
Milk jugs take a beating during shipping, stocking, and everyday handling. That small indentation works like a shock absorber, helping the jug withstand bumps and minor drops without splitting open. This reduces spills for shoppers and product loss for manufacturers.
3. Adds Strength Without Extra Plastic
The circular shape reinforces the jug much like an arch strengthens a building. It increases structural integrity without requiring thicker plastic walls. This keeps milk jugs lightweight, sturdy, and cost-effective—a smart balance of strength and efficiency.
