Elucidation of odour-potent compounds and sensory profiles of Vidal blanc and Riesling icewines from the Niagara Peninsula : effect of harvest date and crop level

I t was hypothesized that the freeze/thaw cycles endured by icewine grapes would change their chemical composition, resulting in unique chemical fingerprint and sensory properties, and would be affected by harvest date (HD) and crop level (CL). The objectives were: 1) to identify odour-active compounds using gas chromatographic and sensory analysis; 2) to determine the effect of CL and HD on these compounds; 3) to determine the icewine sensory profiles; 4) to correlate analytical and sensory results for an overall icewine profile. CharmAnalysis™ determined the Top 15 odour-potent compounds in Vidal and Riesling icewine and table wines; 24 and 23 compounds, respectively. The majority of the compounds had the highest concentrations in the icewines compared to table wines. These compounds were used as the foundation for assessing differences in icewine chemical profiles from different HD and CL. Vidal and Riesling icewine were made from grapes picked at different HD; HI : 19 December; H2: 29 December; H3: 18 January; H4: 11 February (Vidal only). HI wines differed from H3 and H4 wines in both Vidal and Riesling for aroma compounds and sensory profiles. - Three·CL [control (fully cropped), cluster thin at fruit set to one basal cluster/shoot (TFS), and cluster thin at veraison to one basal cluster/shoot (TV)] were evaluated for Riesling and Vidal cultivars over two seasons. Vidal icewines had the highest concentration of aroma compounds in the control and TV icewines in 2003 and in TFS icewines in 2004. In Riesling, most aroma compounds had the highest concentration in the TV icewines and the lowest concentration in the TFS wine for both years. The thinned treatments were associated with almost all of the sensory attributes in both cultivars, both years. HD and CL affected the chemical variables, aroma compounds and sensory properties of Vidal and Riesling icewines and freeze/thaw events changed their sensory profile. The most odour-potent compounds were p-damascenone, cis-rose oxide, 1- octen-3-ol, 4-vinylguaiacol, ethyl octanoate, and ethyl hexanoate. The role of Pdamascenone as a marker compound for icewine requires further investigation. This research provides a strong foundation for the understanding the odour-active volatiles and sensory profiles important to icewine.

Bird depredation of grapes in Niagara vineyards : a novel approach to identifying spatial and temporal trends /

Although local grape growers view bird depredation as a significant economic issue, the most recent research on the problem in the Niagara Peninsula is three decades old. Peer-reviewed publications on the subject are rare, and researchers have struggled to develop bird-damage assessment techniques useful for facilitating management programmes. I used a variation of Stevenson and Virgo's (1971) visual estimation procedure to quantify spatial and temporal trends in bird damage to grapes within single vineyard plots at two locations near St. Catharines, Ontario. I present a novel approach to managing the rank-data from visual estimates, which is unprecedented in its sensitivity to spatial trends in bird damage. I also review its valid use in comparative statistical analysis. Spatial trends in 3 out of 4 study plots confirmed a priori predictions about localisation in bird damage based on optimal foraging from a central location (staging area). Damage to grape clusters was: (1) greater near the edges of vineyard plots and decreased with distance towards the center, (2) greater in areas adjacent to staging areas for birds, and (3) vertically stratified, with upper-tier clusters sustaining more damage than lower-tier clusters. From a management perspective, this predictive approach provides vineyard owners with the ability to identify the portions of plots likely to be most susceptible to bird damage, and thus the opportunity to focus deterrent measures in these areas. Other management considerations at Henry of Pelham were: (1) wind damage to ice-wine Riesling and Vidal was much higher than bird damage, (2) plastic netting with narrow mesh provided more effective protection agsiinst birds than nylon netting with wider mesh, and (3) no trends in relative susceptibility of varietals by colour (red vs green) were evident.

The role of Stl1p in glycerol accumulation in osmotically stressed icewine yeast Saccharomyces cerevisiae K1 V1116

The high sugar concentration in Icewine juice exerts hyperosmotic stress in the wine yeast causing water loss and cell shrinkage. To counteract the dehydration, yeast synthesize and accumulate glycerol as an internal osmolyte. In a laboratory strain of S. cerevisiae, STLl encodes for Stllp, an H+ /glycerol symporter that is glucose inactivated, but induced upon hyperosmotic stress. STLl, was found to be a highly upregulated gene in Icewine fermenting cells and its expression was 25-fold greater than in yeast cells fermenting diluted Icewine juice, making it one of the most differentially expressed genes between the two fermentation conditions. In addition, Icewine fermenting cells showed a two-fold higher glycerol production in the wine compared to yeast fermenting diluted Icewine juice. We proposed that Stllp is (1) active during Icewine fermentation and is not glucose inactivated and (2) its activity contributes to the limited cell growth observed during Icewine fermentation as a result of the dissipation of the plasma membrane proton gradient. To measure the contribution ofStl1p in active glycerol transport (energy dependent) during Icewine fermentation, we first developed an Stllp-dependent (14C]glycerol uptake assay using a laboratory strain of S. cerevisiae (BY 4742 and LiSTLl) that was dependent on the plasma membrane proton gradient and therefore energy-dependent. Wine yeast K1-Vll16 was also shown to have this energy dependent glycerol uptake induced under salt stress. The expression of STLl and Stllp activity were compared between yeast cells harvested from Icewine and diluted Icewine fermentations. Northern blot analysis revealed that STLl was expressed in cells fermenting Icewine juice but not expressed under the diluted juice conditions. Glycerol uptake by cells fermenting Icewine juice was not significantly different than cells fermenting diluted Icewine juice on day 4 and day 7 of Vidal and Riesling fermentations respectively, despite encountering greater hyperosmotic stress. Furthermore, energy- dependent glycerol uptake was not detected under either fermentation conditions. Because our findings show that active glycerol uptake was not detected in yeast cells harvested from Icewine fermentation, it is likely that Stllp was glucose inactivated despite the hyperosmotic stress induced by the Icewine juice and therefore did not play a role in active glycerol uptake during Icewine fermentation.

Inniskillin fonds, 1970-2014, n.d.

Inniskillin Wines was founded by Karl Kaiser and Donald Ziraldo in 1975 in Niagara-on-the-Lake, Ontario. They had met the previous year, when Karl Kaiser, a winemaker and chemist, purchased some grapes from Donald Ziraldo, who owned and operated Ziraldo Nurseries. The two shared a vision of producing better quality Canadian wines and formed a partnership, with Kaiser making the wine and Ziraldo serving as company President. In 1975, they were granted a winery license by the LCBO, the first one granted since 1929. The company name Inniskillin was derived from the Inniskilling Fusilliers, an Irish regiment whose Colonel once owned the land that Ziraldo Nurseries occupied. This was the original site of the winery, although in 1978 the winery moved to the Brae Burn Estate, their current location. In 1982 the winery expanded by 50 acres with the addition of the Montague Vineyard, and another 50 acres was acquired in 1991. The Niagara-on-the-Lake vineyard produces single vineyards bottlings of Chardonnay, Pinot Noir, Merlot and Pinot Grigio/Pinot Gris. In 1984, Karl Kaiser began producing icewine from Vidal grapes frozen naturally on the vine. Inniskillin garnered international acclaim for the quality of their icewines, receiving the prestigious Grand Prix d’Honneur at VinExpo in 1991, for their 1989 Vidal icewine. This established Inniskillin as a producer of world class wines, while also raising the profile of Canadian wines in general. The company branched out their operations, first acquiring vineyards in the Napa Valley in 1989 to form Inniskillin Napa (producing wines under the Terra label), and in 1994 establishing Inniskillin Okanagan in the Okanagan Valley in British Columbia. The Napa valley venture ceased in the mid 90’s, while Inniskillin Okanagan continues to operate. In 2006, Karl Kaiser and Donald Ziraldo left Inniskillin. Kaiser retired, while Ziraldo became chair of the Vineland Research and Innovation Center (2006-2011), and remains involved in the wine industry. In 2007, Bruce Nicholson joined Inniskillin as winemaker. Nicholson continues to produce award-winning wines under the Inniskillin label, receiving the top award, the Premio Speciale Gran Award, at Vinitaly 2009 for his 2006 Gold Vidal and his 2006 Sparkling Vidal Icewine. In 2012, he received several awards for the 2008 Riesling Icewine, including gold at the International Wine and Spirits Competition in London, UK, the San Francisco International Wine Championships, and Selections Mondials des Vins Canada.

Donald Ziraldo Fonds, 1968-2012, n.d.

Donald J. P. Ziraldo, C.M., BSc., LLD was born in St. Catharines, Ontario on October 13, 1948 to Fredrick and Irma (Schiratti) Ziraldo. He graduated Denis Morris High School in St. Catharines in 1967, and received his B.Sc. in Agriculture at the University of Guelph in 1971. In 1974, Ziraldo was running Ziraldo Nurseries when he met Austrian born schoolteacher, chemist and winemaker Karl J. Kaiser. They realized that there was a gap in the premium varietal wine market and decided to plant a premium traditional European variety of grape vine species, the Vitis vinifera. This was an innovation in the Niagara region because the current wine producers were not using premium European grapes at the time. Ziraldo and Kaiser founded and then formally incorporated Inniskillin Wines Inc. in Niagara-on-the-Lake, Ontario on July 31, 1975. Ziraldo successfully lobbied General George Kitching, CEO of the LCBO, for a winery license. In 1975, Kitching granted him a winery license, the first in Ontario since Prohibition ended. From the beginning, there was a division of labour where Kaiser focused on the winemaking and Ziraldo focused on the marketing and promotion of the wines. Ziraldo also became president of the company. Ziraldo and Kaiser worked on improving their winemaking techniques and promoting their products and company. Ziraldo has been called ‘one of the founding fathers of the Canadian wine industry’, and it is widely acknowledged that both men played a large role in the success and growth of the Canadian wine industry. Together they pioneered the estate winery movement in Canada. A major turning point Inniskillin came in 1984 when Karl Kaiser successfully harvested the first Icewine crop from frozen grapes on the vine and bottled Eiswein Vidal (Icewine). In 1990, Inniskillin received worldwide recognition for this Icewine when their 1989 Vidal Icewine won the most prestigious award in the wine world, the Grand Prix d’Honneur, given at Vinexpo in France. This victory has been called ‘the award heard round the world’ and it launched Inniskillin into the international wine arena. At the same time, this helped lift the profile of Canadian wines in general. Inniskillin not only became Canada’s leading producer of Icewine, but it also became known for producing ‘one of the world’s great wines’. After the 1990 award, Ziraldo began a major public relations campaign to promote Inniskillin and build Icewine into a worldwide brand. He travelled broadly every year to promote the brand and products and networked extensively with politicians, celebrities, chefs, sommeliers, etc. To ensure worldwide and long-term success, Ziraldo introduced Icewine to Asia and the United States which were new markets. He developed a new Icewine glass with George Riedel. Tony Aspler has called Ziraldo ‘Canada’s Wine Ambassador’. Ziraldo was President of Inniskillin Wines Inc. (Niagara) from 1975 to 2006. In 1992, Inniskillin merged with Cartier Wines, and in 1993 Cartier Inniskillin Vintners Inc. merged with T.G. Bright & Co. Limited, forming the new company Vincor International Inc. Inniskillin wines was now a subsidiary of Vincor. Ziraldo became a Director at Vincor International Inc. from 1993 to 2004. From 1989 to the mid 1990s, Ziraldo also became President of Inniskillin Napa, in Napa Valley, California. Inniskillin purchased Napa Valley vineyards and produced wines under the Terra label. In 1994, Ziraldo set up a subsidiary estate winery of Inniskillin in Oliver, British Columbia which was called Inniskillin Okanagan Vineyards Inc. He became President of the winery. This started as a partnership between Inniskillin and the local Inkameep Indian Band in the Okanagan. In 2006, Ziraldo left Inniskillin and since that time he has been involved in other Icewine related ventures such as running Ziraldo Estate Winery and producing Ziraldo Riesling Icewine 2007. He also is in partnership with the Niagara based Equifera Estate Winery to produce Equifera Icewine. His most recent projects include planting Picolit grapes in his parent’s hometown, in a project called Picolit Di Fagagna and becoming Managing Director of the Senhora Do Convento Port Winery in Portugal. Donald Ziraldo was instrumental in the creation of the Vintners Quality Alliance (VQA) in Ontario and was its founding Chair from 1988-1995. The VQA was established as a regulatory and appellation system which secured the quality and origin of Canadian wines made under this system. The VQA designation and bottle label gave the consumer confidence that the wines they were purchasing were 100% local products. The VQA system was set up first in Ontario and then in British Columbia.