Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
email: Office@practicalwinery.com
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January/Febuary 2008
WINEMAKING
JOSEPH PHELPS VINEYARDS New fermentors for gentle handling
jackets - a 42-inch high upper "cooling" jacket, a 23-inch high lower "warming" jacket, and a 29 sq. ft. "warming" floor jacket.

The truncated tank measures 7.5 feet diameter at the top, and 8.5 feet diameter at the bottom. The advantage of the truncated tank shape, Hepworth notes, is that the cap breaks better with the wider surface area at the tankbottom.

Each tank has a 12-inch diameter screen tube running the full height of the tank to a bottom valve, used to collect juice for pump-over without skins or seeds, and is also ideal for delestage.

There is a Waukesha model-2065, 3hp centrifugal pump for each tank. This small, gentle pump connects to a piping system with smaller than typical dimensions, intended for slower and more gentle flow of the juice during pump-over. Piping is a 2-inch diameter line from the bottom valve into the pump and a 1.5-inch diameter return line to the irrigator for pumpover, operating at 60 gallons per minute. Other red wine fermentors at Joseph Phelps have 2-inch lines for pump-over by a Waukesha-2085, 7.5hp centrifugal pump with flow rates of up to 110 gals/minute.

Written BY Tina Vierra
Eight ight new red wine fermentation tanks, manufactured by Santa Rosa Stainless Steel (Santa Rosa, CA) were installed for the 2007 harvest at Joseph Phelps Vineyards (St. Helena, CA). The new tanks are outfitted for the gentlest possible handling of red wine during fermentation. Delestage is one part of the primary fermentation process.

Ashley Hepworth, associate winemaker at Joseph Phelps, learned about delestage during a 10-week working sabbatical in 2005, observing and participating in winemaking in Bordeaux. She was based at Chateau Angelus in St. Emilion, working with Merlot, Cabernet Sauvignon, and Cabernet Franc, and she visited several other Bordeaux producers.

"At Cos d'Estournel, I was impressed by the use of delestage, and the results they are achieving," she says. "In their tank room, they have much more dramatically 'pitched,' truncated tanks than I have ever seen."

Delestage involves removing all juice from the skins in the fermentor to another tank, then pumping the juice back over the cap. "The idea is to perform delestage during active primary fermentation and to break up the cap," notes Hepworth.

Dr. Bruce Zoecklein (Virginia Tech) reported in his Enology Notes, "Our delestage research from the 2000 season suggests that this procedure reduced the tannin concentration by 35%, reduced the monomeric anthocyanins by 15%, and increased the polymeric pigments by 59%, compared to conventional fermentation lots. The significant difference in the large polymeric pigment (LPP) concentration, coupled with the reduction of seed tannins, helps to explain the sensory differences between delestage-produced and conventional punch-down fermentations.

"Delestage-produced wines are more fruit-forward and have a richer yet supple and integrated tannin structure. Due to the higher percentage of LPP, it is assumed that the color stability of the delestage wines will be greater as the wines age." (Enology Notes #23, July 2001, Food Science and Technology at Virginia Tech)

Four straight-side, double-wall tanks and four truncated tanks (10-ton capacity with completely insulated side walls, bottom, and top) were installed. Each tank has three glycol

One of four new truncated tanks is placed by crane onto the tank pad. Photo by Fred Lyon.