February 2016 Issue of Wines & Vines
 
SUBSCRIBE   »
 

The Two Faces of Ice Wine Production

Frozen on the vine or in a commercial freezer, both styles are difficult to ferment and clarify

 
by Ray Pompilio
 
 
Grapes for ice wine
 
The Sheldrake Point harvest crew picks grapes for ice wine.

The Finger Lakes is New York’s largest winemaking region, and it is best known for its high-quality Rieslings—from bone-dry to lusciously sweet. Among the latter are a small (but growing) selection of ice wines made from grapes frozen on their vines, often sold at eye-opening prices.

Ice wine was originally known as Eiswein, a German wine produced early in the 19th century, and 150 years later was popularized in Canada, currently the world’s largest producer of such wine. The first commercially produced Canadian ice wines were made in 1983 by Pelee Island and Hillebrand wineries, in Ontario. Two years earlier, however, a Finger Lakes winery, Great Western Vineyards, released an ice wine made from the hybrid grape Vidal Blanc. Vidal Blanc is still a popular choice for ice wine in eastern North America, along with vinifera cultivars Riesling and Cabernet Franc.

Currently, there are two different ways to produce these intense dessert wines—the natural method of harvesting frozen grapes off the vines, and the manipulated method of cryoextraction, where grapes are picked at their normal harvest times and then frozen for use in what is more specifically known as “iced wines.” Although the production techniques are similar regardless of the cultivar and origin of the freeze, the resulting wines can be dramatically different. Both the taste and the price of the wines are determined by the freezing technique used on the grapes. All are bottled in 375ml bottles, and their prices range from $20 to $100 per bottle.

In order to sort out the particulars of making these wines, I spoke with three experienced Finger Lakes winemakers: Steve DiFrancesco, who makes wine at both Glenora Wine Cellars on Seneca Lake and Knapp Winery on Cayuga Lake; Sayre Fulkerson, owner of Fulkerson Winery (Seneca Lake); and Dave Breeden of Sheldrake Point Winery (Cayuga Lake). All three have made ice wines when weather conditions allowed, and they also have made iced wines on a more regular basis. Production of such wines are profiled here, both frozen on the vine and in the freezer.

    KEY POINTS
     

     

  • Ice wine is an intensely flavored dessert wine made from grapes left on the vines until they freeze to about 15° F. But winemakers create “iced wine” using cryoextraction to freeze the grapes.
     

  • The article explores winemaking methods for both wine types in the Finger Lakes of New York. In each case the frozen grapes yield high-sugar, high-acid juice that is difficult to ferment and clarify.
     

  • The two types differ in flavors and in price. Ice wine is more complex in flavor, as the extended hang time and numerous temperature changes break down the grapes in a way that a freezer doesn’t.
     

  • Ice wine can sell for as much as $100 per 375ml bottle.

Fulkerson Winery
Dundee, N.Y.

“Traditionally, ice wine is an opportunistic event,” said Sayre Fulkerson. “It occurs when you have a surplus of grapes, and typically it involves your least-ripe vineyard. It’s a problem looking for a solution, looking for an opportunity.” The Fulkerson homestead close to the western shore of Seneca Lake was founded by Caleb Fulkerson in 1805, and it has been used by the family ever since for crops and fruit production.

In 1975 Sayre Fulkerson graduated with a degree in pomology from Cornell University and became the sixth generation of the family to farm the land. He and his father Roger Fulkerson expanded their vineyards in the 1970s, and in 1979 they purchased the Jensen Juice business from Glenora Wine Cellars. In 1988, following a major hailstorm, Fulkerson decided survival as a grower only was not feasible and began plans for a winery, which he opened in 1989. The estate presently has 100 acres of vineyards, and his wine production averages about 17,000 cases annually.

Fulkerson’s ice wine experience dates back to 1999, when his unpicked Vidal Blanc grapes froze Nov. 7—still the earliest he has ever harvested frozen grapes. “I’m going to let Mother Nature tell me the date,” he said, adding, “It’s very important the fruit enters the press no warmer than 17° F.”

In 2008, when he harvested frozen Merlot and Cabernet Franc in late November, the fruit was 13°-15° F. These grapes, from a neighboring grower, were mechanically picked into 1-ton Welch bins and immediately transported back to the winery, where Fulkerson and his crew hand-shoveled the grapes into a Europress membrane press set at its maximum of about 1.8 bars of pressure. He also has used a Puleo press for these wines. It takes 10-12 hours—and sometimes as long as 24 hours—to press a load of frozen fruit.

“It’s easier pressing naturally frozen grapes than pressing the ones taken out of the freezer,” he said. This is because the freezer grapes are much colder and need to be spread out and warmed before pressing; the grapes on top soften and release their juice more easily. Regardless of how the grapes are frozen, “We end up with a very cloudy juice,” he said. The sugar level in 2008 was 40° Brix with a very high acid concentration. Fulkerson wants yeast suited for high sugar levels and stuck fermentations, and he uses Laffort Zymaflore VL1, isolated in Burgundy and known for its release of floral terpenes.

The yeast is hydrated in water, and juice is added in stages so the yeast is not overwhelmed. Fermentation is done in a 250-gallon tank and will take all winter to complete. If the ambient temperature is too cold, Fulkerson might move the tank to an area about 50° F, but he prefers it to be cooler because, “I don’t mind it sticking at 8%-9% residual sugar,” he said. In order to clear the still relatively cloudy wine, Fulkerson added some pectic enzyme and filtered it with diatomaceous earth.

For the 2008 Cabernet Franc ice wine, he added a small amount of finished still Cabernet Franc to give the ice wine some color. Fulkerson noted that this would be unnecessary if the grapes were harvested at the second or later freeze event, when the grapes would have broken down more on the vines.

Although fermentation and finishing of cryoextracted fruit is basically the same as the naturally frozen fruit, Fulkerson identifies some major differences in producing both wines. “When we do iced wine, it’s typically planned ahead,” he said. Fulkerson has not produced an “opportunistic” vine-frozen ice wine since the 2008 Cabernet Franc, as he chooses to make a more consistent dessert wine less reliant on specific weather conditions. He also cited the smaller expense of production in the vineyard—little crop spoilage and bird damage, no need for bird netting and no winter labor costs. One additional cost is having the grapes frozen elsewhere. In 2014 he had 6.5-7 tons of Vidal and Riesling frozen in 27-pound lugs at nearby Lakewood Vineyards, which took five to six days and cost $900.

Glenora Wine Cellars
Dundee, N.Y.

Seneca Lake’s first winery, Glenora Wine Cellars, is located less than a mile from Fulkerson Winery. Started not long after the passage of New York’s Farm Winery Act of 1976, Glenora now has a 30-room inn and restaurant, and current owners Gene Pierce and Scott Welliver also own Chateau LaFayette Reneau on Seneca Lake and Knapp Winery & Vineyard Restaurant on Cayuga Lake. Combined annual production of the three wineries averages about 75,000 cases.

Steve DiFrancesco is the winemaker for Glenora and Knapp, and he has more than 35 years of experience in the Finger Lakes. After graduating with a degree in biology from Stetson University in 1978 and working at two other Finger Lakes wineries (Gold Seal Winery and Bully Hill Vineyards), he began working at Glenora in 1987. DiFrancesco has remained at Glenora since then, except for 1991-95, when he was winemaker for Lucas Vineyards on Cayuga Lake.

His first ice wine was made in 2008 from Knapp-grown Vidal Blanc with additional vine-frozen Vidal made in 2010, 2012 and 2013. He began making cryoextracted iced wines in 2009 and has continued producing these wines each year.

Glenora’s 2014 iced Vidal Blanc was made from grapes grown at Sawmill Creek Vineyard on the east shore of Seneca Lake. After freezing in Lakewood Vineyards’ commercial freezer for five days, the lugs were loaded onto pallets, wrapped in a heavy tarp and transported to the winery, one 1.5-ton press load at a time. DiFrancesco uses a Willmes bladder press set at two bars, or 30-35 pounds of pressure per square inch. He checks the juice about every 15 minutes to monitor the Brix level, recording the amount and the time it is measured. “Usually the Brix goes up and then levels off. When it begins to drop is when I stop pressing,” he said. DiFrancesco’s records showed juice drips reaching as high as 42°-45° Brix, but the final pre-fermentation total, done in three press loads, averaged 34.8° Brix following racking.

Sulfur dioxide is added at 75ppm, along with Scott Labs KS enzyme at 100 grams per 1,000 gallons. The juice is then settled for a day and racked—and, if needed, settled for one more day. DiFrancesco inoculated with Lalvin K1-V1116 yeast, chosen for its ability to handle fructose and not get stuck with extremely high levels of sugar. Fermentation took place in a 250-gallon tank, lasting for about three weeks at about 65° F. He noted that fermentation of “real” ice wine, with its higher concentration of sugar, could take far longer, sometimes even into late summer.

“When we reach the alcohol level we want, we can rack and sulfur it,” he said. This particular wine was finished at 11.3% alcohol.

He then racks and adds 100ppm sulfur dioxide and also checks for heat stability, adding bentonite if necessary. The wine is then kept cold for a few months, as low as 28° F, if possible. His small tanks are not refrigerated, so he moves them outside in the winter. Even with the length of cold storage, he said, “We’ve never had them throw potassium bitartrate crystals.”

Bottling takes place no earlier than spring, and the 2014 Iced Vidal Blanc wine wasn’t bottled until June 18, 2015. DiFrancesco’s filtering process is very precise, and he noted that some might consider it extreme. The wine was first pad-filtered with Carlson XE675H pads, beginning with 4 microns and finishing with 0.45 microns. The day of bottling it was again pad filtered at 0.45 microns and then final filtered with a Sartorius 0.45-micron membrane cartridge.

The primary purpose of this filtering regime is to get the wine as clean as possible, and to eliminate clogged filter delays on the bottling line that could tie up a number of persons, rather than one person doing the filtering beforehand. Sulfur levels and microbiological stability are closely monitored, and DiFrancesco looks to have 50ppm free sulfur dioxide at bottling. The finished wine bottle ages a minimum of a month, or longer, depending upon the inventory of a previous vintage.

Glenora produced its first two vinifera ice wines in 2014: Riesling and Cabernet Franc. The grapes for both were purchased from and pressed at Sheldrake Point Winery. The purchase cost was considerable. DiFrancesco estimated about 80 gallons of Riesling (at $50 per gallon) were pressed per ton ($4,000 per ton), while the Cabernet Franc juice was $3,000 per ton. Both the Riesling and Cabernet Franc were inoculated with Lalvin K1-V1116 and fermented for about 2.5 months.

DiFrancesco believes there is no real difference in processing frozen grapes, regardless of how they were frozen, and his pressing, clarifying, fermenting and filtering were the same for the Riesling, Cabernet Franc and the iced Vidal Blanc. However, he believes there is a considerable difference in the end products. He said, “To me, iced wines are technically more perfect. The grapes were sound when they were picked, in comparison to the traditional ice wines that have been out two or three months or more, sometimes going through numerous freeze and thaw cycles.”

Sheldrake Point Winery
Ovid, N.Y.

Located on a 155-acre farm on the western shore of Cayuga Lake, Sheldrake Point Winery was founded in 1997. They currently have 44 acres of vinifera grapes and produce about 11,000 cases annually. Their winemaker is Dave Breeden, who has master’s degrees in chemistry and philosophy and a Ph.D. in philosophy from the University of Illinois at Urbana-Champaign. After moving to the Finger Lakes in the late 1990s, he began his wine career as an intern at Cayuga Lake’s King Ferry (Treleaven) Winery in 1999. He joined the winemaking team at Sheldrake Point in 2002 and was named their winemaker the following year.

In 2013 Sheldrake produced natural ice wine from its Cabernet Franc planted in the late 1990s. Breeden identified which Cabernet Franc grapes he wanted to use for ice wine andhad them covered with netting in September 2013. On Dec. 12, 3.16 tons of grapes were handpicked at night.

Utilizing an elevator, the entire load was put into their Bucher Vaslin 50-hectoliter membrane press. Breeden and a representative from Bucher devised a program to press with only an initial rotation, at a pressure of 2 bars, which lasted for 51 hours without any further rotation. A total of 280 gallons of juice was produced, clocking in at 41.5° Brix, TA of 9 g/L and pH of 3.74.

Fermentation began by diluting 5 gallons of juice with 1 gallon of water and inoculating with Laffort VL-1 yeast re-hydrated with Go-Ferm protect nutrient. Small amounts of juice were added over the course of a month, keeping the fermentation between 20° and 30° Brix at all times. Additional yeast was added twice more, and the fermentation continued for 59 days between 60° and 67° F. Rather than reach typical table wine alcohol levels, Breeden said he stops fermentation “when we like the balance.” This fermentation was stopped by chilling on Feb. 12, 2014. He added 300ppm of SO2 to the new wine as well as 8 pounds per 1,000 gallons of bentonite because, “The Cabernet Franc was remarkably protein unstable.”

The wine was kept in the tank at around 60° F for about two months, followed by a series of pad filtrations, all with pads by Carlson that were sourced from Clarifications Technologies Inc. On April 22 the wine was filtered through 10-micron pads, and 10 days later it went through 5.0-micron pads. Five weeks later, on June 16, it passed through 2.0-micron pads, followed four days later with a run through 0.8-micron pads. The wine rested for another 83 days until bottling, when it was sterile filtered with 0.45-micron pads and a 0.45-micron Parker Domnick Hunter membrane supplied by Aftek Inc.

In 2014, Sheldrake Point made an iced apple wine from fruit they purchased, pressed and had frozen; they also made two Riesling ice wines from their grapes. They repeated the netting procedure to protect the grapes from birds and deer. On three nights in January, a total of 8.7 tons of grapes were hand-picked, with the air temperature averaging 14° F. Using the same press and techniques as they did with the Cabernet Franc, the grapes yielded 640 gallons of juice with 40.9° Brix, 10.0g/L TA and a pH of 3.26. Breeden took 300 gallons of the juice from the first two nights and placed it outside in a 300-gallon FlexTank.

The remaining 340 gallons were inoculated Feb. 10 using 6 gallons of juice and 1.5 gallons of water, with 200g of Laffort VL-1 and 250g of Go-Ferm protect nutrient. During the next 3.5 months, 15 more additions of juice were made, maintaining the fermentation between 20° and 30° Brix. The fermentation lasted for 180 days at temperatures between 60° and 70° F. Although the wine did not settle clear, Breeden chose to not add bentonite, deciding instead to put the wine through a seven-stage filtration. Using the same equipment as he did with the Cabernet Franc, he used pads of 10, 5.0, 2.0 (twice), 0.8 and 0.45 microns, finishing with the 0.45-micron membrane at bottling. A notable difference in the wines was the time elapsed for filtering: While the Cabernet Franc filtration encompassed 141 days, the Riesling took only 13 days to complete the filtration.

Whatever became of the 300-gallon FlexTank lot? After the tank was filled, it showed 38.0° Brix, 9.3g/L TA and a pH of 3.41. It was left resting outside, to be used to add to the fermenting tank inside, as part of the Brix-maintenance program employed by Breeden. By spring, the juice still had not begun to ferment. On May 9, however, Breeden discovered the Brix level had dropped to 30.8° and, without inoculation, was clearly fermenting. It was racked to a stainless steel tank nine days later, when 65 additional gallons of juice were added. During the next month, as fermentation continued, the product was monitored for taste, and it was decided to keep the wild fermentation lot separate. Breeden stopped it by chilling on June 13.

About 10 weeks later, Breeden began his regular filtration process, filtering through 10, 5.0, 2.0 and 0.8-micron pads during an eight-day period. Sterile filtration took place Sept. 11, again utilizing the .45-micron pads and .45-micron membrane. Once again, all were Carlson pads, and the membrane was by Parker Domnick Hunter. The wine has received outstanding reviews and was recently named Best Wine of the 2015 Canberra (Australia) International Riesling Challenge, a competition featuring 500 Rieslings from around the world.

Breeden produces ice wines with about 2%-3% less alcohol than many others from the Finger Lakes.

“We like a more unctuous style, so that’s what we do here,” he said, referring to stopping the fermentation for lower alcohol and richer balance.

“The wild-ferment Riesling ice wine is the purest expression of our vineyard,” he said.

Conclusion
All three winemakers agreed that the processing of grapes for ice and iced wines is similar, whether they are frozen in the vineyard or in a freezer. DiFrancesco at Glenora defined the difference, in that the naturally frozen grapes can offer a much more complex product. To him, “The artificially frozen grapes are like lemon meringue, and the naturally frozen are like crème brulee. They’re both good, but if you think you can make the same thing by going to the freezer, you can’t.”

Fulkerson agreed with DiFrancesco’s comments. When asked to compare his ice and iced wines, Fulkerson said, “There’s definitely more to the ice wine,” but he noted that less complex iced wines were still popular with customers looking for a special dessert wine at a lower cost.


Ray Pompilio is a wine writer based in Ithaca, N.Y., where he has close access to the largest concentration of wineries in the state.

 
SHARE   »
Print this page   PRINTER-FRIENDLY VERSION   »
E-mail this article   E-MAIL THIS ARTICLE   »
Close
 
Currently no comments posted for this article.
 
CURRENT MONTH'S FEATURES INDEX ยป