This tests the successful application of the can and the dry film integrity. The can is filled to the rim with a salt solution (1% NaCl, or NaHS04), an electrode is immersed in the solution, and a voltage is applied across the can, 6.3 V for 4 seconds, then the insulation properties of the cured film are measured. The conductance should be <5 mA, preferably <1 mA.
(ii) Flavour
The coated can is filled with a bottled or draught lager beer, left to stand, and then compared against a standard. Points of reference are changes in acidity, bitterness, and any metallic flavour compared to the standard. A trained and skilled flavour (taste) panel is normally used to assess this property.
(iii) Adhesion
This is a standard test used on most organic coatings. In the case of two piece cans, the coated can is pasteurised in a water bath at 82°С for 30 minutes, to simulate the pasteurisation of beer. The can is cooled, dried and then crosshatched and an adhesive tape is applied to the crosshatched area to confirm that the cured film adheres to the body and base of the can.