A Novel Optical Fibre Technique for Measuring Red Winegrape Colour

Colour (total anthocyanins) is one of a number of key quality indicators of red wine grapes. The colour of the final wine is largely determined by the presence of anthocyanins. Increasingly, the sale price of red winegrapes is based, in part, on measurements of the colour. Existing analytical methods for the measurement of grape composition can be expensive and/or time-consuming. This contribution reports on an optical fibre absorption measurement technique, known as optical fibre evanescent field absorption (FEFA), which has been evaluated for its potential to measure the colour of red winegrape homogenate samples. Grape samples, sourced from vineyards in the New England and Hunter Valley region of New South Wales, were used to evaluate the technique using low cost silica and plastic optical fibres.