Research & Development Projects Approved - 2006

2006

·  HEALTH AND SAFETY MANUAL.

The BC wine industry is flourishing. Compared to just over a decade ago, there are currently four times as many wineries producing more than twice as much wine.

The industry is in a state of rapid transition and the BC Wine Institute is committed to provide the resources required to ensure that a safe and healthy working conditions are maintained for all employees at the wineries.

As part of fulfilling this commitment, the BC Wine Grape Council has requested a proposal for the development of a template Health and Safety Program that complies with legislative requirements and industry standards.

The objectives for this project are:

·   Outline of the required elements of a winery specific Health and safety program. This outline would be presented to the BC Wine Grape Council R&D committee.

·   Template a “Health and Safety” manual that can be easily modified by each winery.

·   Training outline to ensure that management and staff are appropriately trained to perform their respective duties in accordance with the safety standards established by each specific winery and WCB

·  ESTIMATION OF SMOKE CONTAMINATION ON WINE GRAPES.

(Principle Investigator is Nigel J. Eggers – UBC Okanagan)

During the fires of 2003, Okanagan vineyards were contaminated with smoke and wines made from these grapes were considered to have an off-odor. At the time, the wine industry was desperate for an analytical method to measure the extent of the contamination. This contamination is likely to be an ongoing problem, since grapes are usually grown in hot dry areas and wild fires will always be a concern. Combustion of wood involves the decomposition of lignins, the structural component of wood, which yield a variety of aromatic phenols. Three of the strongest smelling are guaiacol, 4-methylguaiacol and 4-ethylguaiacol. Guaiacol is described as having a smoky, phenolic, aromatic, burnt, bacon aroma. The aroma threshold of guaiacol in a dry white table wine has been reported as 20 mg/L. 4-Methylguaiacol has a smoky aroma and has a threshold of 65 mg/L in both Ugni-blanc and Merlot wines. The aroma associated with 4-ethylguaiacol is described as smoky, bacon, spicy and clove-like and has a threshold of 110 mg/L.  These compounds may well be indicators for smoke-contaminated grapes that could produce smoky wines.

The goal of this proposal is to develop an analytical technique to measure guaiacol and 4-methylguaiacol in grapes. We have frozen grapes remaining from a previous study. We will then measure these compounds in grapes from Okanagan vineyards that were contaminated by the fire in 2003 and to compare these results with grapes harvested in 2001 and 2002 from the same vineyards. I thus hope to develop the ability to quantitatively determine whether wines will have a “smoky” flavor or aroma.

·  AGEING OF BC WINES.

(Principle Investigator is Hennie J.J. van Vuuren – BC Wine Research Centre).

A brief outline of the nature of the problem facing the industry. Three years ago we started with a project to study the aging capability of outstanding wines produced in the Okanagan valley. Wineries in BC donated wines to the UBC Wine Library where these wines were stored under temperature and humidity controlled conditions. The objectives were to analyze volatile and non-volatile flavour compounds in wines by GC/MS and LC/MS to identify and monitor chemical changes that take place in wines during aging. Each wine was also tasted blind by an experienced tasting panel. After approx. 10 years we should be in a position to provide the industry with valuable data correlating viticulture and enology practices in the Okanagan and the ability of wines to age well. The objectives of this project are:

·   To identify and quantify all volatile flavour compounds in wines by GC/MS. Non-volatile compounds (tannins) will be identified and quantified by LC/MS.

·   To study the chemical changes that take place in BC wines during aging under temperature and humidity controlled conditions. The chemical composition of BC wines will be compared with those of local and international wines of the same varietals and vintages.

·   To correlate the ability of wines  to age with viticulture (rootstock, clone, crop size, and enology practices (yeast strain, barrel aging, micro-oxygenation, etc.).

·   To establish if wines produced from certain varietals age better in certain micro- climates (as determined by GIS mapping by Dr. Bowen) than in other micro-climates

·  ESTABLISHMENT AND APPLICATION OF A SMALL-LOT RESEARCH WINERY TO DETERMINE THE WINEMAKING QUALITY OF GRAPES FROM VITICULTURE RESEARCH.

(Principle Investigator Dr. Pat Bowen – PARC - Summerland)

Proposed is the establishment of a small-lot research winemaking facility at PARC, and use of the facility to make wines from viticulture research projects underway. The facility will enable assessment of the winemaking quality of fruit produced in response to viticultural research treatments, and relationships among fruit and wine composition and wine sensory characteristics. The facility could also potentially be used to assess wine sensory characteristics that result from site conditions (terroir effects). Establishment of the small-lot facility at PARC will create a new training opportunity for students.

Formation of a Research Small-Lot Advisory Committee is proposed. The committee would consist of grape-growers and winemakers who will meet annually to help select the experiments and cultural treatments from which fruit will be sourced for winemaking.  A consulting winemaker from the committee will guide the researchers on the winemaking methods to be used each year.

The facility will consist of 18 jacketed stainless steel small-lot tanks (ca. 100 L) to accommodate four replicates of four viticulture treatments plus two tanks for racking over. The temperature of these tanks will be controlled via a computer-controlled glycol system. Four additional 1000-litre tanks will be available for scale-up winemaking following small-lot evaluation and will accommodate two replicates of two treatments such as the most promising new cultural treatment and current practice (control).

The chemical composition of the fruit, must and wine will be analyzed using standard techniques and those newly developed from ongoing research at PARC. The wines will undergo sensory analysis using a trained panel.  Additionally, the Advisory Committee will give advice on providing wines to industry members for sensory evaluation.

·  ESTIMATION OF BRETT ODORS IN WINE.

(Principle Investigator is Nigel J. Eggers – UBC Okanagan

Brettanomyces is wild yeast implicated in the spoilage of wine and has long been associated almost exclusively with European wines but in recent years is considered to occur in wines from the New World. The compounds that are considered responsible for the Brett odor are 4-ethylphenol and 4-ethylguaiacol. At low concentrations, these compounds are considered by some to add to wine complexity but at high concentrations the wine is considered spoiled and has been described as ‘animal’, ‘barnyard’, ‘stable’, ‘phenolic’, and ‘mousy’. Once this yeast is established in a winery, it is difficult to eliminate. Spoilage of wine by Brettanomyces can be devastating and wineries have had to shut down to remove this contaminant. In 2001, Hennie van Vuuren et al published the results of a three year Brettanomyces study in the BCWI newsletter. They sampled 490 barrels in 49 wineries in the Okanagan and found 6/10 wineries were contaminated with Brett in the first year, 6/13 in the second year and 4/16 in the last year.

The aroma associated with 4-ethylguaiacol is described as smoky, bacon, spicy and clove-like, while 4-ethylphenol is “horsy”, “leather” and “sweaty saddle” like. The threshold of 4-ethylguaiacol is 110 mg/L and 605 mg/L for 4-ethylphenol in a red wine. French and Australian studies have shown that between 30 and 50% of wines have levels of these compounds above their thresholds.

I am developing a simple rapid method for the determination of these two compounds, which will make an accurate and precise high through-put screening of wine for Brettanomyces contamination feasible and should prove invaluable to winemakers. It should indicate to winemakers whether the levels of Brettanomyces contamination are starting to become a problem.

Brett is probably resident in most Okanagan wineries, but is kept in check by current sterile techniques, and the 4-ethylguaiacol and 4-ethylphenol concentrations are very likely well below their thresholds. The concentrations of these two compounds can be used to monitor the effectiveness of Brettanomyces control programs. This analytical method for estimating the extent of Brettanomyces contamination is rapid and will quickly provide information regarding the effectiveness of the sterile techniques.

The study of Brettanomyces infection will take into account many variables and will include the following: age of barrel, cooper, block of grapes, variety of grapes, hygiene (hot versus cold water, sterilizing agent), type of oak used in barrels, sulfur dioxide concentration, cellar temperature, and dissolved oxygen.

·  EVALUATION OF ROOTSTOCK FOR MAINTAINING VINEYARD PRODUCTIVITY IN NEMATOPDE-INFESTED SOIL.

(Principle Investigator Tom Forge – Pacific Agri-Food Research Centre)

To date, there has been little systematic research of soil-related factors affecting vineyard performance in the Okanagan region and growers have relied primarily on recommendations derived from research conducted elsewhere.  Okanagan growers are increasingly reporting blocks of vines and specific areas within blocks of vines exhibiting poor vigor and weak growth.  Nematode analyses from a selection of under-performing vineyard blocks have revealed the presence of several species of plant-parasitic nematodes that have the potential to cause economically-important damage to the roots of grapevines.    

      The use of tolerant or resistant rootstocks is perhaps the most cost-effective and environmentally-appropriate means of dealing with plant-parasitic nematodes.  Prior research from California and Oregon has identified rootstocks that are resistant to some of the genera of nematodes found in BC.  There can be substantial variation, however, among nematode species within a genus, and variation among populations within species, in terms of capacity to reproduce and cause damage to grape rootstocks.  For example, recent research from Oregon and California indicates that 420A Mgt and 101-14 Mgt are generally resistant to ring nematodes (Mesocriconema xenoplax), but populations exist that can reproduce on those rootstocks.  Little information is available on the resistance and/or tolerance of rootstocks to Pratylenchus penetrans, the species of root-lesion nematode present in Okanagan vineyards; prior research in California evaluated rootstock responses to P. vulnus.       

      Soil conditions and soil management practices can influence the pathogenicity of plant-parasitic nematodes.  Composts are reputed to enhance root health and suppress root-pathogens, but actual data on the influences of composts on the nematode-grape root interaction are lacking.  Fine-root growth and turnover, and the mycorrhizal fungi infecting those roots, have direct impacts on the capacity of root systems to acquire nutrients and water.  We propose to (1) evaluate the responses of 4 rootstock options to 5 combinations of Okanagan nematode species-populations, and (2) characterize the influences of compost soil amendments on the nematode-root interaction for resistant and susceptible rootstocks.  Our analyses will focus on assessment of fine-root demography, mycorrhizal colonization, nutrient acquisition and whole-plant physiology in addition to biomass production. 

      The proposed research will be one component of a coordinated BC-Pacific Northwest regional collaborative research effort.  The overall goal of the collaboration is to better understand the pathogenicity of plant parasitic nematodes found in vineyards in the region, extrinsic factors affecting their pathogenicity, and rootstock resistance.  Research at Washington State University (Prosser) will address relationships between at-plant population densities of northern root-knot nematodes (M. hapla) and dagger nematodes (Xiphinema spp.) and yield losses for a limited number of rootstocks.  Research at the USDA-ARS Horticultural Crops Research Laboratory (Corvallis) will address the impacts of ring nematodes on mycorrhizae and whole-plant physiology of a wide array of rootsock accessions.  The research proposed for BC will be improved by linkage with the Washington and Oregon research groups; the BC research will complement the U.S. research by focusing on interactive effects of multiple nematode species (including root-lesion nematodes) and soil amendments on root growth and nutrient acquisition of selected rootstocks.