THE EFFECTS OF GAMMA‐IRRADIATION OF PILSNER BEER

A commercial Belgian Pilsner beer was irradiated with 0, 40, 80 and 120 krad of Cesium 137 gamma ‐rays. Analysis of the resultant beers showed that the analytical data for polyphenolics to a great extent had remained unaffected, that the treatment had no impact upon the liability to haze formation, the pH, the foam stability and the levels of dimethyl sulphide, ethyl acetate, isoamyl acetate, and diacetyl. There was an increase in the concentration of acetaldehyde, and a small decrease in the concentration of iso‐ alpha ‐acids and n‐propanol, the changes being roughly proportional to the dosage applied. The sum of the fast and the moderately fast reducing agents increases with increasing irradiation dosages and in the same way the concentration of slow reducing agents diminishes. The treatment at the same time leads to a drastic loss of colour. The flavour of irradiated beer is totally unacceptable, even at the lowest dosages, the odour reminding one of hydrogen sulphide .