Rotary fermenters: hello again

Wines & Vines, Nov, 1996 by Larry Walker

That now has changed dramatically.

Winemakers who were playing with their first home chemistry set when the machine was developed are now singing the praises of what one California winemaker called those "cement mixers."

"To be honest, I wasn't a real believer," commented Kerry Damskey, winemaker at Associated Vintage Group (AVG) in Hopland, Calif. AVG installed two machines for the crush this fall and two weeks later, Damskey ordered six more for next year's harvest.

"When I first looked at them, I thought they were too expensive and I didn't see much use for them. I like to ferment with a lot of surface area, with a ratio of about two foot to one foot. But now I'm a believer. I'm getting incredible extraction in a very short period and I'm seeing a lot of savings in labor costs as well," he added.

Damskey said that being in the custom crush business gave him a little different perspective. "Not being brand-oriented, small margins in labor saving are significant for us. Also, it's a red wine world now. We are getting more and more clients who want pump overs three times a day." A&G Rotary Fermenters supplied the Associated Vintners machine. They were made by Westec Tank Co. in Windsor, California.

Like many others involved with the rotary fermenters, Damskey is doing side by side studies, bottling wine made in the rotary tanks and wine made by the traditional method.

Bruce Scott of Scott Labs said 1996 was the breakthrough year for rotary fermenters. Scott has been importing Velo machines since 1989, but the action had been pretty slow until now. This year, Scott has installed machines at Burgess, Sterling, Seghesio and at Chateau Ste. Michelle's Canoe Ridge winemaking center on the Columbia River in Washington State.

Scott said that U.S winemakers were beginning to realize that the rotary fermenter was just another tool to shape the kind of wine they wanted.

Tony Dann of ConeTech, marketers of A&G fermenters in the U.S., said several factors were driving the California wine industry interest in rotary fermentation.

There is a stylistic trend towards reds which are full and fruity yet soft in tannins and drinkable early; there is a need to make such wines to consistently high quality standards yet nonetheless at very low labor costs.

Dann said he thought the rotary fermenter's ability to provide automated cap management and rapid turnaround time addressed those needs.

Dann said he believed the great success of rotary fermenters in Australia was because of the extraordinary relationship between A&G Engineering and the Australian wine industry. A&G works closely with winemakers in Australia, getting feedback that has in turn led to a series of improvements to the machine.

What is a rotary fermenter? There are, of course, differences among suppliers, but basically, it's a horizontal stainless steel refrigerated tank that rotates gently in either direction. Inside the tank, fins or paddles move the fermenting grape mass. The machines are designed for easy evacuation and filling and the entire system can be programmed exactly as the user wishes.

The chief benefits are: Shorter fermentation time; ease in maintaining temperature control; ease of cap management; optimal extraction of color, flavor and soft tannins; virtual elimination of hot spots because the rotation breaks down buildup of bunches of skin; virtual elimination of oxidation and microbial spoilage because of the absence of oxygen during the fermentation; use as a storage vessel the rest of the year.

Although most use of rotary fermenters is for red wine, for obvious reasons, they could also be used with aromatic white wines like Gewurztraminer to achieve more aroma extraction. They can also be used like a de-juicer for white wines.

Sterling Vineyards installed six 250 hectoliter Velo machines from Scott Labs for this harvest.

Bill Dyer said he first saw rotary fermenters in action about 10 years ago in Burgundy. Then a few years ago he saw them in use in the Barossa Valley in Australia, used on Shiraz. "I liked what I saw. I wanted to aggressively extract and get the color out without beating up the grapes. Right now, I plan on using them primarily with Pinot noir and Sangiovese, wines that are enjoyable without needing a lot of tannin. But I will be looking at all varieties, including Merlot, which people are drinking young."

Dyer said the rotary-fermented wines could also be used in blending, to soften a harder, tannic wine. "It just gives me more options in terms of extraction and fermentation. I think in California we tend to get stuck on the Bordeaux model, the long and passive maceration and also a warmer fermentation. I'm finding that I can use cooler fermentation, down to about 70 [degrees] and get as good or better fruit retention than with conventional fermentation."

Dyer also mentioned savings on labor costs. "Unloading into presses is really fast. We can drain a tank in 15 minutes. It is designed so the material can just drop into a conveyor belt." (Since this interview, Dyer has left Sterling. - Ed.)