Withycombe, D.A. and Lindsay, R.C.

Abstract
Bottled beer from a single production run was stored at (a) 5 degrees centigrade and analysed as fresh beer, (b) at 21 degrees centigrade for 5 months and analysed as stale beer, (c) at 29 degrees centigrade for 1 month and analysed after 'accelerated storage' and (d) at 29 degrees centigrade for two weeks, rebottled incorporating air and stored at 29 degrees centigrade for two further weeks to give an 'abused' beer sample. The fresh and stale samples were analysed by Withycombes's headspace entrainment system. Both were shown to contain 2 nonenal but the stale sample had a 135% greater concentration. The 'accelerated' and 'abused' samples were analysed by a carbon disulphide extraction porous polymer entrainment procedure. The former had 950% greater concentration of 2 nonenal than the fresh sample, and the abused sample a 750% greater concentration.
Keywords: analysis beer 2 nonenal stale flavour