Interactions between beer and certain packaging materials.
Charalambous, G. and Hardwick, W.A.
Although glass has no effect on the taste of beer, bottles may be coated with a polyethylene formulation to prevent scratching and to give smoother run on conveyors. Accidental contact of this spray with interiors may be encountered with nonreturn bottles. Beer cans are lined with a variety of polymeric materials with possible taste risks and recently thermoplastic cement for body seams on tin-free cans has introduced another possible hazard. The potential taste of can linings was tested by heating the closed empty cans at 100 degrees C for 5 min. With a 10 ml syringe adapted to a Zahm and Nagel piercer, the air in the cans was sampled before and after heting and volatile material detected by gas chromatography. Coatings under test have been applied to glass rod or aluminium foil and incubated in beer for possible flavour effect. Polyethylene crown liners absorbed beer constituents on storage for 4 weeks at 70 degrees F. as shown by discoloration of the liners and by chromatographic analysis. Foreign odour in canned beer was traced to storage of empty cans in cartons which had contained toilet soap and in another instance a varnish flavour was traced to stacking piles of coated and lithographed sheet prior to making up the cans. Whenever lining materials are in contact with beer, flavours may be given off by the polymers. Beer flavours can be potentiated by constituents of the lining, or as shown by air chromatographs on cans which were washed out after containing beer, aroma components can be absorbed by the linings. Chromatographic analysis can show possibly dangerous material but carefully controlled organoleptic tests are the ultimate criteria in examining polymeric materials to be used in contact with beer.
Keywords: beer packaging pollution