by Steve Wagner
Is there anything in wine as unsettling as sediment? Assuming there is not, how can its presence be eliminated or, at least, minimized? This is where cold stabilization comes into play.
The Eastern Winery Exposition program guide explained that Tom Payette’s presentation, “How to Reduce Time and Energy Costs with Cold Stabilization”, would address questions like, “What is the cold stabilization process? How was it performed in years past? What is being done now with great success? What is the future?” Payette also put together a handout for the audience, complete with key reminders from his presentation.
Payette, a winemaking consultant from Rapidan, VA, leaves nothing to be construed as “obvious.” In the aforementioned handout, his first note issues a caveat. “During the winemaking process and before bottling,” he writes, “there may be instability with a juice or wine termed tartrate stability or tartrate instability. Unknowing customers often view these crystals [nicknamed wine diamonds] as a fault and are, therefore, unsure of whether or not to consume the wine. Once a customer is turned off by sediment…it may be difficult to get them to return to your label.”
According to the Oxford Companion to Wine, “In wine tasting, a wine is considered ‘clear’ when there are no visible particles suspended in the liquid and, especially in the case of white wines, when there is some degree of transparency. A wine with too much suspended matter will appear cloudy and dull, even if its aroma and flavor are unaffected; wines, therefore, generally undergo some kind of clarification.”
Purdue University enology professor Christian Butzke carries the thought a step further, “While only an aesthetical issue that requires wine consumer education more than winemaker intervention, it has raised concerns about potential frivolous lawsuits. Thus, the winemaker stabilizes the wine to simulate what would happen if a wine consumer placed a bottle of (white) wine into a very cold refrigerator to chill it down to, for example, 32°F. This cold stabilization is a giant waste of energy and a sad example of unnecessary over-processing of a natural product. However, because consumers expect a visually flawless product, and because more energy-efficient technology — such as a fluidized bed reactor — has not been developed far enough to allow for commercial application, traditional cold stabilization remains the practice of choice.”
In addressing tartrate stabilization, Payette posits a bit of information he labels the 3.65 pH bifurcation. This is a term which, he writes, “was not located in any research literature,” and is a term he uses to describe the phenomenon in his cellar work. Payette maintains all winemakers should understand that for “a wine above a pH of 3.65, one should expect the pH to rise as tartrates form and fall out of solution. For a wine below a pH of 3.65, the pH will drop to a lower pH value. The shift of the pH is usually about 0.06 pH units but it can go as high as 0.19 pH units. This knowledge can be used, factored into and forecasted by the winemaker’s ultimate plans for a certain wine’s pH.”
As a rule, real diamonds only ever depreciate in value. When you buy a diamond from a jeweler, then walk back into the store to sell it back to him, you will get less than you paid just two minutes before.
Wine diamonds are no different, except that if there are too many in your bottled wines, they could depreciate your product forever through a lack of return customers. Wine diamonds, though, don’t have to be forever.
Coping with cold stabilization
by Steve Wagner