Winemakers’ bottle of tricks

What exactly has been done to that wine?

Most consumers assume that wine is an all-natural product; they would be surprised to learn that’s not always the case. Modern-day winemakers have a bag of technical tricks at their disposal to correct faults or enhance flavors. This is especially true of the so-called premium value segment, including many popular restaurant wines. Here are some of these high-tech winemaking manipulations.

Reverse osmosis. This process is commonly used to tame high levels of alcohol, a consequence of improved viticultural techniques and higher temperatures due to global warming, which leads to grapes with more sugar and therefore higher alcohol levels if fermented dry. Wine is pumped through a semi-permeable membrane that allows only small molecules to pass through, i.e., water and alcohol. The water-alcohol mixture is distilled to separate the two liquids, a portion of which is blended back into the wine to achieve the desired ABV.

Micro-oxygenation. This technique introduces a small amount of oxygen into wine maturing in a tank or barrel by forcing the gas through a porous ceramic stone. The oxygen affects the tannins, creating a smoother, softer wine. Mimicking the effects of aging, treated wine is ready to drink sooner. Micro-oxygenation can also mute herbaceous flavors from unripened grapes.

Spinning cone treatment. This “flavor-management” device volatilizes and centrifuges wine into its various components—flavor and aroma compounds and alcohol—which are then reassembled to create the desired aroma and flavor profiles.

Nano-filtration. This next-generation alternative to reverse osmosis is gentler on the wine and more selective as to which compounds are removed. “Nano” refers to a sub-atomic measurement; the liquid phase membrane separation process can filter by molecular weight, shape of the molecule and ionic charge. Nano-filtration is more effective at eliminating alcohol and can also remove taints from Brettanomyces, a wild yeast that gives wine a funky odor and flavor.

Oak additions. Aging wine in oak barrels adds complexity, softens tannins and contributes vanilla, spice and toast flavors. But oak barrels are expensive and aging is lengthy. The cheaper, quicker option is to add oak chips or particles (aka, sawdust) right into the stainless steel tank.


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