An important aspect of beer flavour is its drinkability i.e. how suitable and attractive the beer is for consumption in large quantities. This parameter cannot be assessed fully by objective sensory analysis. A technique based on classification of flavour impressions and consumption of precisely determined beer volumes has been developed. The effects on beers of Czech type of substituting unmalted barley and sugar for malt have been investigated. The use of unmalted barley slows down the primary fermentation and results in a reduction in the proportion of fermentable extract of the wort and a decrease in the degree of attenuation. However the addition of sugar increases the fermentable proportion of the wort extract. The flavour changes resulting from the use of these adjuncts are tabulated. The most obvious is an increase in aroma intensity and in the incidence of estery notes. Particularly with use of unmalted barley, there is a rougher bitterness in the beer and astringent or sharp biting off flavours. With use of sugar, the beer has increased aroma intensity and a fruity aroma. The overall bitterness intensity is lowered and the bitterness quality is harsher. The drinkability of the beer is reduced. Use of sugar shortens the minimum and optimum maturation times, compared with all malt beer, but use of unmalted barley does not change the optimum and minimum maturation times. The flavour changes taking place during maturation are discussed and the minimum maturation times for a 12 degree Plato light beer are: 70 days for all malt beers, 70 days for beers containing unmalted barley, 50 days for beers brewed using sugar. The flavour rapidly deteriorates after the optimum maturation time.
Keywords: accelerated adjunct aroma beer brewing flavour maturation odour taste test