Wednesday, April 23, 2003

In 1958, P. Sudraud measured the absorbtion spectrum of red wine and the result was later republished in Yair Margalit's Wine Chemistry. Here is what he found: Sudraud, P. - Ann. Tech. Agri. 7 (1958) 203. Well there you have it. By diluting my samples and plotting as wavelength vs absorbance (2-log%T), i get curves with a definate maximum peak near 540 nm and a local minimum around 430-450 nm, like Sudraud's young wine. Black Swan 2002 Shiraz: Beaulieu Vinyards 2000 Syrah: What does this all mean? Margalit says, oxidized phenolic compounds absorb light near 520 nm, giving them a brown hue. Are these compounds deeply colored enough to account for variety in wine color? How about taste? What phenolic compounds are these? And finally, are there other compounds that can be traced by some qualitative means? (Continued ...)

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