Adhesive Test on Capsulated Stoppers in Wines and spirits

Solution

• Motorised torque testing system
• Custom-designed chuck grips for secure holding of capsulated (Bar-Top) stoppers

Benefits

• Quickly detects stoppers with weak adhesive bonding performance
• Ensures firm and even gripping of smooth and coated surfaces

Requirement

A capsulated stopper (T-top, bar-top, or Altop®) is a natural or synthetic cork body glued into a top cap crafted out of wood, polymer, ceramic, metal, or glass. These stoppers are typically used for beverages such as spirits and fortified wines to be served and consumed over several servings. They are highly favored by bar staff and customers for their easy opening and resealing properties and are commonly found in products such as whiskey, brandy, tequila, port, and other spirit products.

Bonding the cork body to the top cap can be done manually or automatically, depending on the scale of production and the choice of materials. The cork, adhesive, and capping methods are selected to meet regulatory requirements. These stoppers are often employed in high-end products and require durability in successive extraction and twisting while maintaining integrity between the cork and the cap.

Thus, an assessment of the adhesive force between the stoppers and caps is an essential quality-control step for both the producer and the customer. Consistency and repeatability of a test are crucial to evaluate the performance of different stopper types, materials, and sizes while ensuring user-friendliness and flexibility of the testing apparatus.

Solution

To measure the bonding strength, the cork portion is held firmly in one grip while the cap is secured in another. Controlled torque is then applied to the assembled stopper until failure occurs, either through adhesive breakdown or material rupture. The maximum torque value is recorded and assessed against To measure the bonding strength, the cork portion is held firmly in one grip while the cap is secured in another. Controlled torque is then applied to the predefined quality standards to determine acceptance.

To measure the bonding strength, the cork portion is held firmly in one grip while the cap is secured in another. Controlled torque is then applied to the Presto’s motorized torque testing system operates at a uniform rotational speed, eliminating inconsistencies caused by manual variation. Fast data acquisition allows accurate measurement of peak torque, even when bond failure or material failure occurs.

Testing can be complicated by the potential for coated corks and stiff caps to slip. To prevent slipping and maintain secure gripping, chuck grips with specially designed jaws are used. These grips are engineered to apply uniform gripping force, avoiding specimen damage and slippage and ensuring repeatable test results for various stopper types and sizes.

Test Equipment

• Presto Motorised Torque Tester
• Precision Torque Transducer (6 N·m capacity)
• Digital Torque Indicator Systeme
• Customised dual chuck grips for capsulated stopper testing