Acid: Warrior for clean wine? Ask The Wine Ladies. October 2008

Dear Wine Ladies,

I recently heard from some-one who is quite the authority on wine that wines are 100% bacteria free due to the alcohol content. In fact I understand wine was the beverage of choice in lieu of water in former times specifically for this reason. If you could confirm this for me it would be greatly appreciated.



Dear John,

Thanks for the great question. It is true that wine was considered to be a safer drink than much of the available water up until the 18th century. And still today seasoned travelers often opt for a glass of vino over one of water. Many of the threatening pathogens to ones health were either inhibited or killed off by the consuming of wine. As to whether the alcohol in wine can guarantee all wines are 100% bacteria free, we have to disagree. We decided to consult with an oenologist (winemaker) for his opinion and a full scientific explanation. Yes, alcohol does indeed impede the livelihood of some bacteria; however it by no means alleviates the potential presence of many others. In fact it is the pH level of wines, which is the strength of the total acids in wines that is the real warrior against bacteria. This is one of the most important variables winemakers monitor during the winemaking process.

If the pH level is not within the accepted range of approximately 3.00-3.60 (the normal pH of water is 7, and our blood is much more alkaline at 7.3) various wine spoilage bacteria are able to survive. When you think of alcohol level as a protective barrier to bacteria, let us consider alcohol swabs of close to 100% alcohol composition; even at that, indeed the majority of bacteria could not survive, but not necessarily all. So, yes, alcohol does provide somewhat of a defense against bacteria in wines, but the real protector is the pH level, or the strength of the acids. One final footnote, microbiologist Mark Daeschel at Oregon State University, a believer in the disinfectant properties of wine, as of last year was awaiting a patent on a wine cleaner he developed for use on kitchen counters and even fresh fruit.


The Wine Ladies, Georgia and Susanne


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