May 31, 2008, by  Karl Storchmann (Journal of Wine Economics)

Back in 1987 at the Los Angeles County Fair, a blend of Chenin Blanc and Riesling by Ariel’s Vineyards of San Jose was awarded a gold medal. It was evaluated by many judges at a blind tasting. Nothing special you would think. But Ariel’s wine was de-alcoholized and contained less than 1% of alcohol and competed with regular white wines. This was worth a longer report in the New York Times.

Given the treatment that a wine has to undergo in order to lose some or all of its alcohol, this is a fairly amazing result. De-alcoholized wines have been produced in Europe and the United States for decades. There are several methods to partially or totally extract the alcohol from the wine ranging from heating (which also removes most flavors) to more advanced methods such as cold filtration, spinning, reverse osmosis and transport osmosis (see also Wine Business Monthly).

In reverse osmosis, a small portion of wine is passed over one side of the fine-bore filter membrane under pressure, and smaller molecules (water, alcohol and some acids) are forced through the membrane creating the permeate. This permeate is then distilled, and the original water that was removed is added back thus lowering the alcohol content of the original wine.

Transport osmosis is a membrane technology that uses the difference in vapor pressure to draw the alcohol in the wine through the hydrophilic membrane and into the stripping water. The stripping water can be re-circulated in the system until the alcohol content of the feed wine and the stripping water are essentially the same.

In the spinning cone the liquid is spun at high speeds until the alcohol separates, a small amount of which is then returned to the drink.

Given that in many high-quality wineries winemakers want to move their wines as little as possible, oftentimes working with natural gravity and free flows, these de-alcoholization procedures sound pretty invasive. Hard to believe that they do not affect the taste of the wine. But earning a gold medal at a county fair is a relative achievement. Some of you may remember Orley Ashenfelter’s report on wine judges that was published in the "Journal of Wine Economics" entitled “Tales from the crypt: auctioneer Bruce Kaiser tells us about the trials and tribulations of a wine judge.” (click here).

At the AAWE Conference in Portland from Aug 14-16, Josselin Masson (Montpellier SupAgro), Philippe Aurier (University of Montpellier II) and Francois D’Hauteville (Montpellier SupAgro) will present a new experimental study about consumer assessments of alcohol-reduced wines.

The authors conclude that, “on the sensory level, reduced alcohol in wine does not seem to be a negative factor, and it is even possible to create a positive taste preference for low-alcohol products, as the blind testing evaluations reveal. When the consumer is informed about the alcohol level, consumption level of low and of high alcohol wines do not significantly differ.”  

 

Here is their abstract:

This paper addresses the potential of fostering the sensory and psychological acceptability of a product which has been significantly altered. In the case of low-alcohol red wine, we conducted a longitudinal study of consumption at home, allowing us to measure both the quantities consumed and the hedonic evaluations before and after exposure to the product. During the first phase, 24 consumers were divided into two separate groups, and, over a two week period, were given wine containing a reduced alcohol content of 9%, as well as a “standard” wine containing 12.5% alcohol. During the second phase, 40 consumers were given a wine containing 12% alcohol but with a label indicating 10.5% or 13.5% alcohol, according to the same alternate protocol. The results of the first blind testing suggest a good sensory acceptability of the reduced alcohol wine which persisted after the trial of the two products. The second phase, with information provided, indicated an equivalent psychological acceptability of the supposedly “weak” alcohol level and the supposedly “strong” alcohol level because the quantities of the products consumed were equal regardless of the information accompanying the products. This result is inconsistent with previous studies comparing the acceptability of wines containing varying degrees of alcohol. Although  the size of the sample made it difficult to obtain significant results, our result  suggest that, while prolonged exposure has not changed the usual behavior, it seem to have a (positive) effect on expectations  towards the innovation.