Scott Harvey Says: Wine and pH

by Scott Harvey

Schooled in winemaking in both Germany and California, winemaker Scott Harvey was crucial to putting Amador County on the California wine map in the 1980s. After years spent propelling such wineries as Santino, Renwood, and Folie a Deux to success, he launched his own Scott Harvey Wines with his wife Jana in 2004. We're thrilled to have him take over the regular Wine.Woot guest blogger position. See his first post here.

We as wine makers do not make wine, Mother Nature does. It is a natural process of fresh juice to vinegar. By understanding the biochemistry and the life cycles of the organisms involved we can direct and halt the process at the point where the human species likes to drink it rather than at the vinegar stage where the fruit fly prefers it.

Ever since Louie Pasteur figured out that it was yeast and bacteria that convert juice to wine and vinegar, we have been able to determine the conditions needed to foster the growth of the organisms we desire and the retardation of those we don’t desire for the production of fine wine.

One of the best tools in determining the environment we want to create for Mother Nature to do her job in creating fine wine is monitoring pH. Basically, pH is the measurement of free hydrogen ion concentration in the solution. For some reason, and I don’t know why, they chose 7 for neutral pH. Maybe some wooter out there does know why and can tell us. Everything above 7pH becomes more and more basic as the OH ions increase and everything below 7pH becomes more and more acidic as the positive hydrogen (pH) ions increase. Wine is an acidic solution that is produced in the range of 2.8pH to 4.2pH.

Not until the late 80s was the development and reliability of the pH meter such that we could use it in daily winemaking. Therefore, before that we relied on the measurement of total acidity to tell us what we needed to know. Today, still many winemakers make their decisions on TA rather than pH. It was a German winemaker Ed Friedrich, winemaker for San Martin in the early 70’s that showed Dr. Richard Peterson, then winemaker for Monterey Vineyards, how important pH was. Monterey was a new high quality wine region with a particular problem of producing grapes with extremely high malic acid levels thus forcing the winemakers to find a new way to evaluate the wine. Ed showed us when we are tasting acidity we are really tasting pH. pH will predict taste much better than TA ever has.

Up until 1996 I made wine based on TA. In 1996 Dr. Peterson (my mentor) brought me to Napa Valley to take over Folie a Deux winery. It was at Folie a Deux winery that I learned how to use pH in making my decisions on creating the right environment so that Mother Nature would transform those wonderful grapes into the wines we all enjoy.  

This blog is really an introduction to the next blog that will explain how pH plays a role in developing either new world wines (Parker Wines) or old world wines (food wines). Stay tuned.