Andrew G. Reynolds

Vinification effects on the sensory, colour and GC profiles of Pinot noir wines from British Columbia

Abstract Analytical and sensory profiles were obtained for Pinot noir wines fermented with two yeasts (Lalvin EC-1118, P; Lalvin L-2056, L) and four vinification techniques: high (T), ambient, cold and modified-cold temperature (M) fermentations. Wines were analysed for titratable acidity, pH, ethanol, colour, total phenolics, flavonols, tartaric esters, anthocyanins and volatile constituents. Sensory descriptive analysis was conducted using 12 judges to evaluate colour, aroma, flavour, body and overall quality. Wines from the M vinification had the most red colour, body, tropical fruit and spicy aromas and had the least vegetal character. Wines from the T vinification were the most vegetal. Increased ester concentration (mainly acetates) and total volatile compounds were found in wines from the M vinification with yeast P in comparison to the other vinification methods and yeast L. Principal component analyses distinguished four distinct groups of wines based on 33 main volatile constituents. Partial least square regressions revealed strong relationships between sensory and instrumental colour measurements in terms of red colour intensity ( r =0.88) and red hue ( r =0.87).

Fumigation of table grapes with acetic acid to prevent postharvest decay

Acetic acid (AA) fumigation controlled decay of Summerland Selection 494 and Selection 651 table grapes in repeated trials over a 3-year period when grapes were fumigated with 0.27% vol/vol AA and stored for 6 weeks at 2 or 5°C. Fumigation of Selection 651 at approximately 2-week intervals with AA or SO 2 controlled both Botrytis and Penicillium decay and reduced berry shatter equally in two separate years. No significant difference occurred between SO 2 and AA treatments in yield components (cluster and berry weight), fruit composition (°Brix, titratable acidity, pH, and color), and degree of rachis drying.

Canadian terroir: characterization of Riesling wines from the Niagara Peninsula

Abstract The Niagara Peninsula (Ontario, Canada) is thought to have distinct viticultural areas (‘bench’, ‘plains’, ‘lake’), but the uniqueness of wines from these regions has not been documented. Therefore this research was undertaken to document the nature and magnitude of the terroir differences using 14 commercial Riesling wines from producers who utilized grapes from the ‘Beamsville Bench’ (‘bench’) and the ‘Niagara Plains’ (‘plains’) regions. The sensory characteristics of the wines were profiled using descriptive analysis (DA) coupled with univariate and multivariate statistics. Six trained judges evaluated 10 aroma (pineapple, melon, grapefruit, lemon/lime, apple, peach/apricot, rose/floral, honey, diesel/petrol, mineral/flint), six flavour (pineapple, melon, grapefruit, lemon/lime, peach/apricot, honey), two taste (acidity, sweetness), and three other (alcohol, body, finish) sensory attributes. Data were analyzed using analysis of variance, step-wise discriminant analysis (SDA) and principle component analysis (PCA). Wines from the ‘bench’ had significantly higher grapefruit, pineapple, melon and lemon/lime aromas, more acidity and greater lemon/lime flavour than the ‘plains’ wines. ‘Plains’ wines were more diesel/petrol-like in character. A PCA of the data, using the most relevant sensory descriptors (as determined by SDA), indicated that 68.7% of the variability could be explained in the first two dimensions, with factor one accounting for the lemon/lime, grapefruit, melon and acidity of the wines and factor two representing the mineral/flint character.

Odor Potency of Aroma Compounds in Riesling and Vidal blanc Table Wines and Icewines by Gas Chromatography–Olfactometry–Mass Spectrometry

This study aimed to elucidate the odor potency of aroma compounds in Riesling and Vidal blanc (syn. Vidal) table wines and icewines from the Niagara Peninsula using stir bar sorptive extraction-gas chromatography-olfactometry-mass spectrometry. Dilution analysis determined the most odor-potent compounds in Vidal and Riesling icewines (n = 2) and table wines (n = 2) from a commercial producer. The top 15 odor-potent compounds in each wine were identified and quantified, resulting in 23 and 24 compounds for Riesling and Vidal, respectively. The most odor-potent compounds were β-damascenone, decanal, 1-hexanol, 1-octen-3-ol, 4-vinylguaiacol, ethyl hexanoate, and ethyl 3-methylbutyrate. In general, icewines had higher concentrations of most aroma compounds compared to table wines. Through computation of odor activity values, the compounds with the highest odor activity for the icewines were β-damascenone, 1-octen-3-ol, ethyl octanoate, cis-rose oxide, and ethyl hexanoate. In table wines the highest odor activity values were found for ethyl octanoate, β-damascenone, ethyl hexanoate, cis-rose oxide, ethyl 3-methylbutyrate, and 4-vinylguaiacol. These findings provide a foundation to determine impact odorants in icewines and the effects of viticultural and enological practices on wine aroma volatile composition.

Canopy Management and Enzyme Impacts on Merlot, Cabernet franc, and Cabernet Sauvignon: II. Wine Composition and Quality

Merlot, Cabernet franc, and Cabernet Sauvignon vines in Niagara-on-the-Lake, Ontario, were subjected to four treatments in a randomized complete block experiment: hedged control, cluster thinning at veraison (CT), basal leaf removal (BLR), and CT+BLR. Musts from each treatment replicate (CT+BLR excepted) were thereafter either left untreated or treated with one of ColorPro or Color X enzymes. In most cases, CT and CT+BLR treatments had the highest wine anthocyanin and phenol concentrations and the highest color intensities (A420 + A520). Leaf removal resulted in small increases in wine color intensity and anthocyanin and phenol concentrations. Cluster thinned and BLR treatments both reduced titratable acidity (TA) and increased pH relative to controls, but BLR tended to be more effective than CT. The CT+BLR treatments usually resulted in the lowest TA and the highest pH. Enzyme treatments increased wine TA and reduced pH and typically increased color intensity, total anthocyanins, and phenols. Both viticultural and enological treatments had noteworthy impacts on individual wine phenolic compounds and anthocyanins, although the viticultural treatments were more efficacious. The viticultural treatments enhanced intensities of several aroma and retronasal descriptors (e.g., black fruit, black pepper, tobacco) and reduced those of others (e.g., bean/pea, mushroom). The CT+BLR treatment has the potential to substantially improve fruit and wine composition in cool-climate regions; negatively, excessive leaf removal could result in lowered ethanol and undesirable increases in pH. Enzyme treatment has the potential for increased color intensity, but with occasional increases in TA.

Canopy Management and Enzyme Impacts on Merlot, Cabernet franc, and Cabernet Sauvignon. I. Yield and Berry Composition

Merlot, Cabernet franc, and Cabernet Sauvignon vines in Niagara-on-the-Lake, Ontario, were subjected to four treatments in a randomized complete block experiment: hedged control, cluster thinning at veraison (CT), basal leaf removal (BLR), and CT+BLR. Musts from each treatment replicate (CT+BLR excepted) were thereafter either left untreated or treated with either ColorPro or Color X enzymes. CT and CT+BLR treatments reduced yield per vine and crop load but had inconsistent effects on cluster weight, berries per cluster, and berry weight. BLR alone had few effects on yield components. CT and CT+BLR treatments generally had the highest soluble solids (Brix) in berries and musts and in most cases had the highest berry and must anthocyanin and phenol concentrations and color intensities (A420 + A520). Leaf removal resulted in slight increases in berry and must color intensity, anthocyanin and phenol concentrations, and little or no increase in Brix. CT and BLR both reduced titratable acidity (TA) and increased pH relative to the control, but BLR tended to be more effective than CT. BLR and CT+BLR treatments usually resulted in the lowest berry and must TA and the highest pH. Enzyme treatments increased must TA and reduced pH and typically increased color intensity, total anthocyanins, and phenols, but viticultural treatments generally had a greater magnitude of effect. The CT+BLR treatment has the potential to substantially improve fruit composition; negatively, excessive leaf removal could result in lowered Brix and TA and undesirable increases in pH. Enzyme treatment has the potential for increased color intensity, but with occasional increases in TA.

Impact of Exogenous Abscisic Acid on Vine Physiology and Grape Composition of Cabernet Sauvignon

In the Niagara Peninsula, cool years delay veraison, thus shortening the growing season and adversely affecting grape maturity. Exogenous abscisic acid (ABA) could potentially hasten veraison, and improve grape composition in cool and wet years. Two experiments were conducted in a Cabernet Sauvignon block in Niagara-on-the-Lake, Ontario, in 2008 and 2009. Both years were characterized by higher than average rainfall and lower temperatures. The first experiment was initiated one week preveraison and consisted of four treatments applied three times at two-week intervals: an untreated control and 300 mg ABA/L applied to the full canopy, clusters only, and leaves only. The second experiment had three treatments: 0 (control), 150, and 300 mg ABA/L applied to clusters only. In both years, the control still had clusters with 20% green berries two to four weeks after experiment initiation. Following treatment, berries had a lower ABA uptake rate than leaves. Both ABA rates hastened the onset of veraison. In both years the transpiration rate, leaf Ψ, and fruit composition were most affected in the leaves-only and whole canopy treatments. At harvest, Brix was higher and the berry weight was lower in the ABA treatments than the control. Total anthocyanins and total phenols also increased in most ABA treatments. Berries from clusters treated with the highest ABA rate showed a higher red-blue color intensity and also had highest anthocyanins and phenols content compared to berries from other treatments. The treated vines showed enhancement in individual anthocyanins and acetylated anthocyanins, with significant changes in the ratios of cyanidin, petunidin, and malvidin occurring among the treatments. Exogenous ABA was effective in accelerating onset of veraison and improving the grape composition of Cabernet Sauvignon.

Aroma compounds in Ontario Vidal and Riesling icewines. I. Effects of harvest date

Icewine is a sweet dessert wine made from pressing grapes naturally frozen on the vines. It is likely that freeze/thaw cycles endured by icewine grapes change their chemical and sensory profiles due to climatic events. Our objective was to determine the influence of harvest date on icewine must and wine basic chemical variables and aroma compounds. Riesling and Vidal icewines were made from grapes picked between December 2004 and February 2005; Harvest 1 (H1): 19 December; Harvest 2: 29 December; Harvest 3 (H3): 18 January; and Harvest 4 (H4): 11 February (Vidal only). Icewine musts differed in titratable acidity and pH (Vidal only). All basic wine chemical analytes differed across harvest dates. All aroma compounds differed in Vidal and Riesling wines. Highest concentrations for most aroma compounds were in the last harvest date; 16 of 24 for Vidal and 17 of 23 for Riesling. The latest harvest date had highest ethyl isobutyrate, ethyl 3-methylbutyrate, 1-hexanol, 1-octen-3-ol, 1-octanol, cis-rose oxide, nerol oxide, ethyl benzoate, ethyl phenylacetate, γ-nonalactone and β-damascenone. H1 had highest ethyl butyrate, ethyl hexanoate, linalool, 4-vinylguaiacol and ethyl octanoate. Based on odor activity values, the most odor-potent compounds were β-damascenone, cis-rose oxide, 1-octen-3-ol, ethyl octanoate, ethyl hexanoate, and 4-vinylguaiacol across harvest dates. PCA found most aroma compounds associated with the last harvest date, 4-vinylguaicol excepted, which was associated with H1. Harvest date was considered a discriminating dimension using canonical variant analysis for volatile compounds.

Interactions of Vine Age and Reflective Mulch Upon Berry, Must, and Wine Composition of Five Vitis vinifera Cultivars

ABSTRACT Four- and 14-year-old Cabernet Franc, Cabernet Sauvignon, Pinot Meunier, Pinot noir, and 15-year-old Riesling vines located at Thirty Bench Vineyards in Beamsville, Ontario, were assessed in terms of vine age (2002 and 2003) and reflective mulch treatments (2003) with respect to berry, must, and wine composition as well as wine sensory attributes. In 2002, but not 2003, old vines had higher yields, clusters per vine, cluster weights, and berry weights than young vines. Berries from young vines tended to have higher Brix and lower titratable acidity (TA), pH, and total phenols than those from old vines in 2002; in 2003, age showed little impact on berry composition. Wines made from young vines in 2002 were higher in TA, and often lower in pH, color intensity, and anthocyanins than those from old vines, while in 2003, young vines produced wines with lower TA, and higher pH, intensity, and total phenols. Reflective mulch showed few effects on the berry, must, and wine composition of the red wine cultivars; however, mulch increased free and bound terpenes in the Riesling berries. Wines produced from young Cabernet Sauvignon and Cabernet Franc vines exhibited more intense vegetal aromas and flavors than those from old vines in 2002 but not in 2003. The red wines made from the mulched vines generally exhibited the least amount of vegetal aroma and flavor. Reflective mulch also led to less perceived acidity in Riesling wines.

Visible-Near Infrared Reflectance Spectroscopy for Nondestructive Analysis of Red Wine Grapes

Composite samples of intact grape berries were collected weekly from veraison until harvest. Each sample comprised ~400 berries selected following the preharvest row sampling protocol specified by the vineyard manager. The grape cultivars and corresponding number of samples of each collected in 2009 and 2010 were as follows: Cabernet Sauvignon (43, 36), Cabernet franc (83, 80), and Syrah (38, 36). Reflectance spectra for the composite samples in a wavelength range of 350 to 850 nm were collected with a diode array spectrometer. Chemical analyses for soluble solids content, Brix, pH, titratable acidity (TA), total phenols, and total anthocyanins were carried out for all samples. Chemometric calibrations for corresponding reflectance data were developed using trained partial least squares regression models with several preprocessing methods (smoothing, normalization, differentiation) and subjected to variable selection by recursive feature elimination. Trained models were externally validated with data from the alternate year. Best performing models for Brix, pH, TA, phenols, and anthocyanins in 2009 had root mean square errors (RMSEP) of 0.65, 0.05, 0.59 g/L, 31.2 mg/L, and 75 mg/L, respectively, with corresponding R2 values of 0.84, 0.58, 0.56, 0.27 and 0.65. The best 2010 models had RMSEP of 0.65, 0.05, 0.86 g/L, 27.9 mg/L, and 111 mg/L, respectively, with corresponding R2 values of 0.89, 0.81, 0.58, 0.25, and 0.17. The 2009 calibrations were used for estimating Brix and pH from spectral data of the samples collected in the next growing season and yielded RMSEP performance of 0.87 and 0.05 and R2 values of 0.71 and 0.56, respectively. Principal component analysis decomposition of 2009 and 2010 reflectance data showed similarities in the resultant loadings, indicating a similar underlying data structure.