Thursday, April 24, 2003

I took a spectrum of an Amarone I had previously tasted: The absorbance spectrum of a 1:5 dilution is plotted in black, while the transmitance (%T divided by 100) of the wine is the red dotted line, both enumerated on the y axis against wavelength (nm) on the x axis. The graphs are superimposed to give a feel for the relationship between absorbance (light that gets absorbed) and transmitance (light that gets through). Sudraud's 'phenol' peak near 520nm is very pronounced in the absorbance graph, even though this wine is 5 years old. (This really delicious raisin wine from Italy is still $10 at Trader Joe's. I'm tempted to buy and hold a few bottles for a few years and see what they do, 'spectrum-wise' of course. Amarone can withstand decades of cellar time.) But now look at the transmitance curve above. Only red (and maybe some orange) light is transmitted through red wine according to this spectrum and my (overly blue-yellow sensitive) vision agrees. I'd be interested in hearing from any physiological psychologists or color-vision specialists: does the tiny bit of light indicated by the absorbance minimum at 430 nm provide enough light to give a wine a 'purple' cast? I'm not ready to say no, but I am going to continue to keep my eye on the transmission spectrum which shows only red light coming through red wine. (Continued ...)

comments