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Questionable ‘Premium’ Grapes

TroubleShooting

Jim Neame (and the rest of our group) — Victoria, British Columbia asks,
Q

Although I live in Victoria, British Columbia I use California grapes, and this year our winemaking group purchased 8.5 tons. However the pH was all over the map and I am wondering whether or not you could answer the following questions. The “old vine” California Zinfandel grapes tested out as follows: 21 °Brix, pH 3.97, TA 6.2. First question: Is it reasonable to assume the pH from these fields would have been similar last year and would be the same next year? Or can pH be all over the map from year to year from the same fields? The Cabernet Sauvignon had a pH of 3.67, Brix of 22.5 and a TA of 6.0. The Merlot had a pH of 3.8, Brix of 23.4 and a TA of 6.0. In all cases I added tartaric acid to reduce the pH for a total of 4.0 cc per liter for the Zinfandel, 2.5 cc per liter for the Cabernet and 3.0 cc per liter for the Merlot. I would very much appreciate your comments as I am having a serious argument (perhaps a misunderstanding) with the supplier who calls these grapes “premium.” Should grapes with a pH as high as this still be promoted as “premium,” which has also attracted a premium price.

A
That’s an interesting data set you present there. What I’m about to tell you, please take with many grains of salt because I am not privy to the growing locations of your California Zinfandel, Cabernet Sauvignon and Merlot grapes and, for instance, would expect very different quality numbers from a Zinfandel grown in Dry Creek Valley in Sonoma County vs. a Zinfandel (especially one grown for White Zinfandel purposes) from the Central Valley of California. Before I go too much farther, let me state that you must keep liberally applying said salt shaker because I’m not privy to the details of your purchase contract and your own expectations of what’s acceptable quality for you. What I’m about to tell you is only my opinion; if you wish to employ me as a legal witness to testify in court, please contact my editors at WineMaker magazine (tongue firmly in cheek. . .). That all being said: I think you have a Brix problem as well as a pH problem . . . and perhaps a “relationship problem.” Let’s start with your