Sensory analysis of beer

To illustrate descriptive analysis, I will draw from both the wine and beer industry. Oregon State University s Sensory Science Laboratory, located in the Department of Food Science and Technology, is heavily involved in wine and beer research. The principle problems and solutions in the sensory analysis of wine and beer should be transferable to other products. Common wine descriptors, such as soft, hard, fat, are ambiguous. What do soft or hard mean when referring to wine The goal of descriptive analysis is to use precise terms, even referring to specific chemical entities when possible. In the wine industry, objective sensory analysis must overcome the historical romance of wine. 

More recently, studies of wine and beer have initiated techniques of statistically vaUd sensory analysis. Scientific studies involving wine continue in these areas, building on past discoveries. Natural phenols as desirable dietary components and monitors of storage and aging reactions are currently active fields. Viticultural research, as well as enological, continues to improve grapes and the wines made from them (11). 

Bisulfite addition products are readily formed at wine pHs (1, 23, 24). The bisulfite addition product is thought to be a more sensory-neutral compound and may be exploited by winemakers as a means of decreasing the aldehydic character of wines (1). Bisulfite addition has also been used to mask the stale flavor of beer which is thought to be largely due to the formation of trans-l-noneml (25). Kaneda et al. (25) used HPLC with fluorescent detection of an o-phthalaldehyde derivative to quantitate and identify individual aldehyde-bisulfite products, however, only acetaldehyde-bisulfite adducts were observed in commercial beers with this method. Hydrolysis of the adducts occurs at pHs greater than 8, therefore by adjusting the pH prior to analysis, total aldehydes (free plus bisulfite bound) can be estimated. At low pHs accurate estimation of free aldehydes is complicated however, by analysis conditions which alter the equilibrium between bound and free forms (temperature, dilution, solvent extraction, analysis time, etc.). 

Fig. 23.11 Discriminant analysis of sensory data on thirty three lager beers, (a) Result (b) Interpretation of result. Code A = North American beers, B = British beers, C = Continental European beers. (After Brown and Clapperton [54].)...

Results of cluster analysis of sensory and physicochemical data on beer After CLAPPERTON [50] ... 

The electronic nose arrays have today successfully been used in a vast number of applications. The electronic noses are particularly appealing in food analysis since they resemble the traditional way of controlling the quality of foodstuffs. The electronic nose is already applied as a complement to sensory test panels in the food industry for product quality classification. Examples of applications are classification of grains [6] and beer [7]. Examples of other consumables tested are tobacco [8] and perfumes [9]. Applications in other areas such as environmental control and pulp and paper quality are also reported in over five hundred references currently found in the literature on electronic noses. 

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