Issue link: http://winesandvines.uberflip.com/i/101495
WINEMAKING Comfortable With Crossflow One-step filtering, improved performance and mobile services propel crossflow filtration By Paul Franson T hough early problems held back the use of crossflow filtration in winemaking, it has now become widely used both at large wineries and small producers enlisting the help of mobile services. The equipment is relatively expensive to buy, yet crossflow filtering has a number of advantages compared to other types of filtration. It is one-step filtering that involves less handling and processing, so it has less potential for oxidation compared to the traditional multi-step filtration. It wastes much less wine than plate-andframe or DE filters. Wineries also don't have to deal with diatomaceous earth (DE), which is regulated by the Occupational Safety and Health Administration as a potential health hazard, and there's no waste DE to discard. Crossflow filtration removes suspended solids, yeast and bacteria. Of course, some wineries like to claim they don't filter for marketing purposes, but users agree that today's crossflow filters do not affect color, alcohol or taste. How it works Wine flows across the membrane surface under pressure and at high velocity. The Highlights • rossflow filters offer one-stop filtering C without the waste and safety issues of DE or waste of frame filters. • sers attest that crossflow filters don't afU fect taste and aroma, and they may improve quality by reducing astringency and tannins. • obile crossflow-filtering services make M sense for wineries producing less than 5,000 cases in places where they are available. 52 W in e s & V i ne s JANUARY 20 13 Longtime Hess Collection winemaker Randle Johnson uses filtration equipment from Bucher Vaslin. velocity of the crossflow circulation and high turbulence prevents a build up of solids on the membrane surface, keeping it clean with a self-scouring action. Wine and dissolved solids continuously pass through the membrane as permeate, while bacteria and suspended solids are retained by the membrane and concentrated further with each pass through the system. Conventional "dead-end" filtration causes a cake of solids to build up on the filter surface, requiring frequent filter cleaning or replacement. Crossflow filtration also reduces the wine loss associated with set up and retention in the filters. It can have a loss of less than 1%. Winemakers' views Some artisan winemakers won't talk about their use of filters, but others are happy to share their experience. Steve Reeder of Simi Winery in Healdsburg, Calif., has had a Pall crossflow filter since 2005. When he came to the winery, Simi was using only plate-and-frame filters. "They really abused the wine and there was terrible waste," he said. He didn't want to bring in DE due to its issues of disposal and safety considerations, so after trying a number of crossflow systems he says he found the Pall superior. As Reeder is also the general manager of the winery, he found a quick payoff: The first wine he filtered was the 2004 Landslide Cabernet, which sold for $35. "We would have gotten 14,000 cases with the previous filters. Instead we got 14,800. Those extra 800 cases at $35 (per bottle) paid for the filter by themselves." Reeder had tried a crossflow filter in 1998 at another (now defunct) winery, but it was premature. "We got an 8º-10º rise in heat across the filter, and there were other problems, too. It was unacceptable." The filter is important since Simi doesn't fine its red wines. Reeder takes steps in the vineyard and uses extended maceration to encourage long-chain particles to precipitate too, but he finds the crossflow filter works well. "The Pall filter is fantastic. It's the opposite of what people think. We find that the process increases quality. The 0.2-micron size takes a little edge off the astringency and bitterness.