Our friend was over last night just hanging out and relaxing and we decided to see the movie, "Bottle Shock", based on what is now referred to as "The Judgement of Paris", a wine competition that took place in 1976, during the U.S. Bicentennial. I recalled the discussion we had online in the Wine Quality UC Davis course that was initiated by Bob Hurlbett. The discussion centered around the scene where the Chateau Montelena chardonnay had turned brown in the bottle and Jim Barrett, disgusted with himself, was about to go back to the law firm he left.
In the movie, Jim's son Bo Barret and Sam, a winery intern, take a bottle of the brown chardonnay to UC Davis. An enology professor says that he's heard of but never seen an example of a white wine so painstakingly protected from O2 exposure that it turned brown after bottling. He predicts, much to the delight of Bo and Sam, that the wine will lose the brown color and turn clear in a day or two.
Another classmate, Tom Nelson responded to Bob's discussion thread saying that Bo Barrett is an acquaintance of his and asked Bo what his take was on the '73 Chardonnay. The movie actually took liberties because in reality the wine had turned pink and not brown.
From Bo Barrett:
"Hi Tom
The 1973 Chard post bottling color change event was a phenol instability called pinking. It is very briefly described in Zoecklein et al "Wine Analysis and Production". I am certain I have seen better descriptions elsewhere, perhaps Peynaud. Mike Chelini has experienced several during his career at Stony Hill."
Bo Barrett
Master Winemaker
Chateau Montelena Winery
At the Top of the Napa Valley
"Always drink upstream from the herd"
Tom Nelson provided an excerpt from Zoecklein et al, "Wine Analysis and Production", 1995, page 141:
Development of a red blush in white wines, a reaction called pinking, is occasionally observed. Where there is an overall reduction in oxygen exposure, pinking is reported to be the result of rapid conversion of flavenes to the corresponding red flavylidium salts. With reference 7-10, one can see that flavenes are formed in an acidic medium by slow dehydration of corresponding leucoanthocyanins.
In the presence of oxygen, flavenes and leucoanthocyanins are converted to brown pigments. Under reducing conditions, however, accumulations of flavenes may occur. Subsequent rapid exposure of wine to air, such as may occur during transfer, filtration or bottling, converts flavenes to their red flavidium salts, which confer a pink blush to the wine".
Grady Wann, our instructor added:
Although the mechanism of the pinking reaction is not known, there is quite a bit of evidence that the reaction involves the oxidation of a phenolic compound(s). It is usually associated with white wines of certain susceptible varieties that are protected from oxygen during winemaking and then see some air at bottling. The color change can be transitory and is usually avoided when juices see oxidative treatment. (Apparently the phenolics with pinking potential are oxidized at the juice stage and drop harmlessly out of solution.) If the potential for pinking is identified, the wine can be treated with PVPP for stability. (PVPP can also be effective after the fact.) It is an uncommon problem, but does happen. See Andy Waterhouse' research note in AJEV 52: 156-158 (2001).
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