The SOMM Journal

August/September 2014

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Page 88 of 119

{ }  89 stop people doing it, though. Open-top fermenters have also been cited by some as being useful in the fight against alcohol. I have heard figures quoted suggesting that as much as 1% alcohol reduction is possible through alcohol being blown off during the fermentation process. The two main alcohol reduction technologies are, as mentioned above, the spinning cone and reverse osmosis. The "spinning cone" contains around 40 upside down cones, half of which are fixed and half spin. In a vacuum environ - ment, the cones spin the wine into thin liquid films, and a cool vapor rises off the wine, carrying the volatiles from the liquid. In the first pass, the ultra-light component consisting of the delicate flavors and aro - mas is carried off and condensed. This is known as the "essence" and is saved for later, to be recombined with the wine. The second pass takes off as much alcohol as you want to remove. Theoretically, you could then recombine the remaining low alcohol wine with the essence and the alcohol and end up with the same wine you started with. Reverse osmosis is a type of filtration system. It's complex to explain in brief, but it works in a similar way to the body's kid - ney: While conventional filtration systems have their flow blocked by the filtration membrane, which becomes clogged, here the flow is tangential to the membrane, which helps prevent the pores becom - ing blocked, although it requires a much larger membrane surface. It's also known as "cross-flow" filtration. The consequence of this is that you need lots of very long filtration tubes all bundled together for reverse osmosis, making the system expensive compared with standard filtra - tion systems, although it is still portable and very much cheaper than the spinning cone column. The cost of the spinning cone machine is around one million dol - lars, whereas a reverse osmosis machine co sts around $30,000 and is small enough to be moved around, making it possible to do alcohol reduction in the winery. The rules can be a problem for this sort of technology. In the U.S., spinning cones have been authorized for alcohol reduc - tion, but in Europe this technique has until very recently only been allowed on an experimental basis (you are allowed to treat 50,000 hectolitres, but it can't leave the country of origin). In November 2008, the rules were changed to make reduc - tion by up to 2% alcohol legal in the E.U. This could her ald a wider uptake of these techniques in Europe. In the U.S., both are commonplace. Clark Smith estimates that 45% of premium Californian wines are alcohol-adjusted by either reverse osmosis or the spinning cone. These technologies could have a role to play where climate and site conspire to make it hard to get physiologically ripe grapes with sensible sugar levels. They're tools, and while some people may feel uncomfortable about them because they appear to be so interventionist, it could be that their use would make what are already good wines better. The tantalizing possibility remains that wines that speak more eloquently of their origins—the vine - yard site or terroir they came from—could be realized with the use of technology. Finally, the use of yeasts that are less efficient in converting sugar to alcohol could work. These are yeasts that uti - lize metabolic pathways that mean that they produce less alcohol for each unit of sugar used, by redirecting sugars to other metabolites, such as glycerol. There is currently a lot of interest in this field: Researchers, aware that genetically modified yeasts are unacceptable to most consumers, are trying to identify pathways and then select yeasts that demonstrate these desirable properties. The key thing is to develop yeasts like this that don't make the wines taste a bit weird. In the Vineyard There's a general principal in winemaking, which is that if you are going to intervene, the earlier you do it the better. So the frontline in the fight against high alcohol is in the vineyard. The easiest way to get lower alcohol wines is to pick the grapes earlier. Can this be done without a quality loss? Perhaps, in some cases. Certainly, for many producers high alcohol is a by-product of a stylistic choice to aim for ever-more ripeness. But in other cases, winemakers are reluctant to sacrifice adequate flavor development for a degree or two of lower alcohol. Homogeneous ripeness levels across vineyard blocks are helpful. One contribut - ing factor to high alcohol is the presence of raisined, super-ripe berries alongside those that are simply properly ripe. These raisined berries contribute sugar to the must and little else. It also follows that if you are waiting for the last grapes to get ripe in a block of uneven ripeness, then some of the grapes will be super-ripe. A key aspect of vineyard management is therefore to zone vineyards into homogeneous blocks. The use of water is also a key manage - ment too, where irrigation is available. Portuguese viticulturalist David Booth, a student of famous flying "vine doctor" Richard Smart, describes irrigation as being like the joystick of an aircraft as it comes into land. Small inputs of water at the right time can allow physiological ripe - ness to catch up with sugar ripeness in warmer climates: The water reduces the sugar ripeness, buying you time to leave the grapes hanging a little longer. A Question of Style: Food- Friendliness and Ageability It will be interesting to see whether the backlash against ever-higher alcohol levels in wine results in a trend of lower alcohol levels, particularly in red wines where things have gone a bit crazy in recent years. Would some wines that currently weigh in at 14.5% alcohol be better at 13.5% alcohol? Tasting through a line-up of the same wine at different alcohol levels indicates that alcohol can mask aromas and add sweetness and body. This suggests that many richer red and white wines from warmer climates might actually taste better, more savory and more food-friendly at slightly lower alcohol levels. They might also age better, too: It has been suggested that high alco - hol wines don't age all that well, although this could be because of style issues. Picking later results in red wines with softer, more developed tannic structure that simply has less evolution ahead of it. Now that alcohol reduction has been legalized in Europe, this whole area will be an interesting one to track over the next few years. It could be that alcohol "fine- tuning" will increasingly be seen as part of the winemaking repertoire in much the same way that fining and filtration are cur - rently seen as necessary steps in finishing a commercial wine before bottling.

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