Posts Tagged: wine
While many of us cherish the mystique of popping a wine cork, screw caps are becoming more commonplace in the wine industry. Half a century ago, screw caps were associated with cheap rotgut wine, but now they have replaced corks in many premium wines and at many of the world’s best wineries.
Wine bottles are sealed primarily in three ways — natural corks, synthetic corks or screw caps. All have their advantages and disadvantages, and most certainly their proponents and opponents. While synthetic corks never gained much of a foothold in the wine industry, screw caps are being studied more frequently for their efficacy and quality.
While screw caps were originally thought to be airtight, resulting in the unpleasant aroma of hydrogen sulfide inside some sealed wine bottles, screw caps have been developed with different levels of permeability. Most aluminum Stelvin caps are lined with a polyvinylidene chloride–tin foil combination (Saran-Tin), or a polyvinylidene chloride–polyethylene mix (Saranex); each yielding different permeabilities, and chemical and taste profiles in the wine.
Research is weighing the value of screw caps on wine quality and consumers’ ability to taste differences in wine bottled with a cork or a screw cap.
The study, which will be completed next year, is not touted to give a definitive answer to the best type of wine closure, but it will, according to Waterhouse, give winemakers reliable information on which to judge the type of closure that works best on their wines. (Watch Waterhouse explain the study in a video.)
An earlier study at Oregon State University, and reported in ScienceNews, said that consumers could not discern a difference in Pinot Noir and Chardonnay wines capped with natural corks or screw caps.
Perhaps what merits future study is the type of linings in screw caps. As screw caps continue to gain a foothold in the wine industry, it’s reasonable to assume that additional research on cap linings will produce additional options for winemakers, resulting in high-quality wines with greater longevity.
Based on research studies and wine experts’ judgments, here are some advantages and disadvantages of different types of wine closures:
- Traditionalists claim that "real" corks allow healthy gas exchange for flavorful wine
- Some claim that good sources of natural cork are dwindling
- Not all natural corks are alike, resulting in variable cork properties
- Higher chance of “corked” wines and trichloranisole (TCA) taint
- Considered expensive and unpopular with consumers
- Many synthetic corks let too much air into the wine bottle
- They’re often difficult to remove from the bottle, and to re-cork the bottle
- Less chance that wines will be “corked,” and probably fewer tainted wines
- Some say that air-tight screw caps are “suffocating” to wines
- Corks and screw caps? Can wine consumers taste the variation? UC Davis study
- Wine corks are going: the screwcaps are winning. HubPages
- Cap or cork, it’s the wine that matters most. ScienceNews
- Great wines under cork and screw cap. Forbes
- Corks vs. screwcaps. Total Wine & More
- Chateau Margaux corks a problem with a screw cap. The Wall Street Journal
- 7. Cork vs. screw cap: what’s all the fuss about? Imbibe Liquid Culture
Nearly half of the 55 unusual winegrape varieties in a plot at the UC Kearney Agricultural Research and Extension Center in Parlier displayed enough promising characteristics to prompt a cooperating vintner to make 25 small lots of wine.
The research at Kearney is designed to expand the wine industry’s options in the San Joaquin Valley, currently California’s top grape growing district in terms of production, but lowest in terms of price.
“Most of the popular wine varietals – Merlot, Cabernet Sauvignon, Chardonnay – are at their best in somewhat cooler climates. So we are looking for grapes that make superior fruit in warm climates,” said Matthew Fidelibus, UC Cooperative Extension specialist in the Department of Viticulture and Enology at UC Davis.
Fidelibus is supervising the production at Kearney of winegrape varieties that were collected from countries such as Spain, Greece and Italy, where the climate mimics the valley’s hot days and warm evenings. In the research plot, the vines exhibit a wide range of vigor, productivity and fruit quality.
While Fidelibus is gathering data on each variety’s yield potential, cluster architecture, amenability to mechanization and other viticultural characteristics, winemaker Constellation Brands is monitoring the winegrapes’ potential to produce distinctive, flavorful California wines.
“We need a breakthrough variety,” said Oren Kaye, a research and development winemaker at Constellation Brands. “Many of the wines we produced showed significant promise.”
Currently, 80 percent of California wine is made from fewer than 10 types of winegrapes, with the most popular white being Chardonnay and the most popular red Cabernet Sauvignon.
Kaye says the market is ripe for something new, perhaps Fianio, a white wine with a fresh, young style evoking flavors of melon and grapefruit, or the stylistically unique Marselan Noir, a red wine with bright cherry flavor that pops.
“Millennials own tomorrow,” Kaye said. “They are more accepting of things that are new, as long as it is good. At a restaurant, they think nothing of pulling out a smart phone to look up a wine they haven’t heard of before.”
Fidelibus comments in the video below about a recent tasting event that featured four winegrape varieties from the Kearney trial:
A new winery, brewery and food-processing complex began operations this fall at UC Davis. Part of the Robert Mondavi Institute for Wine and Food Science, the technologically sophisticated facilities will be used to teach students, conduct research, and solve practical problems related to foods, beverages and health.
The south wing of the new complex is home to the August A. Busch III Brewing and Food Science Laboratory, which includes the brewery, general foods-processing plant and milk-processing laboratory. The complex’s north wing houses a new teaching-and-research winery. The complex is adjacent to a 12-acre teaching-and-research vineyard and across a courtyard from the departments of Food Science and Technology, and Viticulture and Enology.
The new $20 million, 34,000-square-foot complex, funded entirely by private donations, will be the first winery, brewery and/or food-processing facility to earn LEED Platinum certification, the highest environmental rating awarded by the U.S. Green Building Council. (LEED stands for Leadership in Energy and Environmental Design.)
Features include onsite solar power generation and a system for capturing rainwater and conserving processing water. Stored rainwater will be used for landscaping and toilets.
The winery (right) will capture carbon dioxide, a natural byproduct of fermentation, thus reducing the building’s energy requirements for air quality and temperature control.
Other features include maximum use of natural light, food-processing equipment that minimizes energy and water requirements, use of recycled glass in flooring, interior paneling recycled from a 1928 wooden aqueduct, and use of sustainably certified lumber.
The new brewery will showcase the latest in brewing technology, as well as a sophisticated laboratory for conducting research and training students. It also provides commercial brewers and suppliers with a small-scale facility to test new recipes or processes.
The general foods- and milk-processing laboratories have been built to meet state and federal food- and dairy-grade standards. Products processed there will be used in sensory and nutritional evaluations.
Research in the food-processing pilot plant will examine alternative food-processing methods and their nutritional effects, nutritional quality and shelf life of fresh-cut fruits and vegetables, nutritional enhancements from food-processing “waste” products, and improved food formulations.
The milk-processing laboratory will support research on separation of milk components into functional ingredients, processing of milk modified by different feed rations, and processing of milk from cows bred for specific characteristics.
Dozens of private donors helped make the complex a reality, including a $5 million contribution from the late winemaker, Robert Mondavi, and a $5 million pledge by the Anheuser-Busch Foundation.
Other major donations were made by Ronald and Diane Miller and by a group of winery partners led by Jess Jackson and Barbara Banke of Kendall-Jackson Wines, and Jerry Lohr of J. Lohr Vineyards & Wines. The Department of Viticulture and Enology’s Board of Visitors and Fellows also made significant contributions.
California tomato processors and growers contributed more than $2.5 million to the food-processing pilot plant. Morning Star Packing Company provided a lead gift of $1 million for the food-processing plant. Hilmar Cheese Company also stepped up with a $250,000 pledge.
In all, more than 150 individuals, alumni, corporations and foundations contributed funds for the new winery, brewery and food-processing complex.
(Thanks to Patricia Bailey, UC Davis News Service, who provided content for this post.)
Learn more at http://greenrmi.ucdavis.edu.
August visitors to California wine country can see winegrapes ripening – green changing to gold, red and purple. This is the critical final stage of development, and its success drives one of the state's economic engines, with wine sales generating $18 billion in revenue in 2009. Wine country is also a tourist magnet and a job generator; the industry has a $61.5 billion economic impact statewide each year.
If this is a typical year, California will produce 90 percent of the nation’s wine. In normal vines, the ripening period means sugars and pH increase, while acids (primarily malic) decrease. Other compounds such as tannins develop, and all these factors contribute to the flavors and aromas in the wine that eventually results. (See healthy Cabernet Sauvignon, at right.)
However, in recent years growers have become increasingly concerned about a malady that appears during this phase. Known as “berry shrivel,” this disorder leads to shriveling of berries on a cluster.
There are several kinds of berry shrivel. Of greatest concern to growers and winemakers are sugar accumulation disorder (SAD), in which grapes turn flabby and lack sugar, and bunchstem necrosis, (BSN) in which grapes turn raisin-like on the vine, losing juice and often developing undesirably high sugar content. (See California Agriculture) Either of these disorders makes the fruit less desirable for winemaking, with yield and production losses.
Berry shrivel afflicts both red and white varieties. Cabernet Sauvignon and Merlot are the major red varieties to be affected so far. Among the white varieties, Sauvignon Blanc, Chardonnay, Semillon and Riesling have shown symptoms.
The malady usually becomes apparent when winemakers or sugar samplers are in the vineyard tasting fruit. Once detected, vintners will often make a pass through the vineyard just ahead of the harvest crew to drop this fruit due to its low sugar content and off-flavored juice.
"Berry shrivel usually affects a small proportion of a vineyard's fruit – perhaps 5 percent -- but in particular vineyards and years, shriveling can affect more than half of the crop," says Mark Krasnow, who was a postdoctoral student at UC Davis and is now at the Eastern Institute of Technology in Hawke’s Bay, New Zealand. "In some years and some sites, wineries will decide not to harvest a vineyard due to the amount of shrivel. Fortunately this is rare."
The origins of SAD and BSN are a mystery, in spite of research investigations. Krasnow and his colleagues at UC ran a battery of high-tech tests to determine the factors involved, but found little consistency in results and to date, all tests for pathogenic organisms have been negative.
Whether due to SAD or BSN — berry shrivel occurs in vineyards all over the world, managed under different climates, making it a globally significant problem in winemaking.
"The irregularity of when and where (or if) SAD and BSN occur makes them very difficult to study," Krasner notes. Tests conducted by UC Davis Foundation Plant Services were negative for phytoplasmas, closteroviruses (leafroll), fanleaf viruses, nepoviruses and fleck complex viruses.
“It is possible that SAD has multiple causes, and that one of those causes might be a pathogen,” Krasnow says. “In some cases, all the fruit on a vine is affected, even clusters that appear outwardly normal. In other cases, it is only the symptomatic fruit that develops abnormally.”
Preliminary studies suggest that SAD can be propagated by chip budding, but vine-to-vine spread has not been seen, according to Krasnow. Future studies will focus on tests for a causal organism and a more careful examination of the metabolism of fruit affected by this disorder.
Bunchstem necrosis also varies in symptoms and whether effects occur on clusters or whole vines, and can occur at bloom or at ripening (veraison). Future studies will examine varietal differences in susceptibility having to do with xylem structure, the importance of concentrations of mineral nutrients, and other cultural factors.