Abstract
Determination of the I. T. T. (Indicator Time Test) value of beer has so far been conducted by the visual measurement. However, this visual judgement of the critical point, at which 80, o, of added dyestuff is accurately decolorized, is very difficult. We attempted to estimate the I. T. T. value more correctly using a spectrophotometer. On the basis of the following facts and observations, spectrophotometric determination of the I. T. T. value has been proposed. The absorption maximum of 2, 6-dichlorophenolindophenol was observed at 520 mμ, but the absorption of beer was hardly ever recognized at this wave length. Walpole's buffer solution was used for stabilizing the dyestuff at a pH similar to that of beer. Ethanol contained in beer did not affect the absorption of dyestuff. It was also found that the optical density of the dyestuff was proportional to the concentration both in water and in beer.
