Download or read book The Impact of Fining on the Chemical and Sensory Properties of Washington State Chardonnay and Gew rztraminer Wines written by Melissa Sanborn and published by . This book was released on 2008 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Chemical and Sensorial Effects of Plant based Fining Agents on Washington State Riesling and Gew rztraminer Wines written by Laura Ellen Hill and published by . This book was released on 2009 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Impact of Wine Components on the Chemical and Sensory Properties of Wines written by Remedios R. Villamor and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The wine matrix includes a variety of compounds that influence wine quality. The overall objective of this study was to examine the relationship between the matrix components and sensory attributes of wine. To address the issue on wine quality as related to tannin and polymeric pigments, the effect of initial tannin concentration, storage time and temperature on chemical and sensory properties of young bottled Cabernet Sauvignon and Merlot wines was studied. In general, storage treatment resulted in a significant increase in small polymeric pigment (SPP) with a decrease in anthocyanin (p [less than equal to] 0.05). Tannin concentration was directly related to large polymeric pigment (LPP) and correlated with perceived astringency (r = 0.882). Increased perceived bitterness was associated with storage at 32 & ordm;C for 70 days. In addition to tannin content in wine, further experiments investigated the interaction of tannin with ethanol and fructose concentrations on the headspace concentration of eight odorants in model wine. In general, increased tannin concentration exhibited a salting-out effect while fructose induced a salting-in effect, both of which were largely dependent upon ethanol concentration. The net magnitude effect was a reduction in the odorants' headspace concentration dominated by ethanol. Odor detection thresholds increased between 2 and 10,000-fold, lowering the odor unit values (OUV). The impact of ethanol, tannin and fructose concentrations on the sensory properties of model red wines was also evaluated. Principal component analysis (PCA) differentiated the model wines based on factor 1 (floral, fruity and caramel), factor 2 (earthy and herbaceous) and factor 3 (sulfur, spicy, woody, and bitterness). Analysis of variance (ANOVA) results showed a significant impact of ethanol concentration on these factors (p [less than equal to] 0.05). Tannin and fructose, and all interaction effects were not significant. These results highlighted the influence of major wine components and their interactions on sensory perception. Viticulturists and winemakers are suggested to consider the information obtained in this research when making decisions to optimize wine quality.

Download or read book Chemical and Sensory Influences of Sur Lies on Chardonnay Wines written by Gregory Tazwell La Follette and published by . This book was released on 1991 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Ethanol Tannin and Fructose on the Sensory and Chemical Properties of Washington State Merlot written by Anne Carolyn Secor and published by . This book was released on 2012 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical and Sensory Assessment of Astringency in Washington State Red Wines written by Josie L. Landon and published by . This book was released on 2007 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of 4 ethylphenol and 4 ethylguaiacol on the Sensory Properties of Washington State Cabernet Sauvignon and Syrah written by Sarah Michaux and published by . This book was released on 2011 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensory Effect of Regulated Deficit Irrigation and Mechanical Pruning on Washington State Wines written by Edward Joseph Kronfli III and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many challenges face the contemporary wine-grape producer in the current global wine market, and for many viticultural regions in the world amongst the main concerns are lack of water, labor shortages and tight economic margins. The use of mechanical winter pruning and regulated deficit irrigation are two options available to growers, however many remain apprehensive about their effects on the resultant wine. In this study, the sensory effects of mechanical pruning on Syrah and deficit irrigation on Chardonnay are tested via a general descriptive analysis. The mechanically pruned Syrah wines was shown to be not significantly different from the wines made from the hand-pruned vines when harvested at equal levels of ripeness. The deficit irrigated Chardonnay wines only showed an increase in floral character and decrease in musty character when water stressed between fruit-set and verasion. It should be noted that these differences were small, with a difference of 5.5% and 3.4% for floral and musty, respectively. Data shown in this study is promising for producers looking to adopt new techniques and technologies. However, producers should remain cautious as different sites and cultivars may react differently.

Download or read book Understanding Wine Chemistry written by Andrew L. Waterhouse and published by John Wiley & Sons. This book was released on 2016-06-07 with total page 775 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wine chemistry inspires and challenges with its complexity, and while this is intriguing, it can also be a barrier to further understanding. The topic is demystified in Understanding Wine Chemistry, Special Mention awardee in the 2018 OIV awards, which explains the important chemistry of wine at the level of university education, and provides an accessible reference text for scientists and scientifically trained winemakers alike. Understanding Wine Chemistry: Summarizes the compounds found in wine, their basic chemical properties and their contribution to wine stability and sensory properties Focuses on chemical and biochemical reaction mechanisms that are critical to wine production processes such as fermentation, aging, physiochemical separations and additions Includes case studies showing how chemistry can be harnessed to enhance wine color, aroma, flavor, balance, stability and quality. This descriptive text provides an overview of wine components and explains the key chemical reactions they undergo, such as those controlling the transformation of grape components, those that arise during fermentation, and the evolution of wine flavor and color. The book aims to guide the reader, who perhaps only has a basic knowledge of chemistry, to rationally explain or predict the outcomes of chemical reactions that contribute to the diversity observed among wines. This will help students, winemakers and other interested individuals to anticipate the effects of wine treatments and processes, or interpret experimental results based on an understanding of the major chemical reactions that can occur in wine.

Download or read book Exploration Into the Influence of Malolactic Fermentation Parameters and Pre fermentation Juice Treatment on Chardonnay Mouthfeel written by Anthony Sereni and published by . This book was released on 2016 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mouthfeel is one of the most important quality parameters of Chardonnay wines. Malolactic fermentation (MLF) is an important process in wine production, and influential to wine mouthfeel, with the reduction in acidity being particularly important for cool climate wines that generally have higher acidity such as Chardonnay. MLF is typically induced by the addition of Oenococcus oeni after the completion of the alcoholic fermentation (AF) but can occur concurrent with AF by inoculating O. oeni simultaneously with the fermentative yeast Saccharomyces cerevisiae. We investigated the effect of MLF inoculation timing as well as the temperature of MLF and the presence of the non-Saccharomyces yeast Torulaspora delbrueckii on Chardonnay wine mouthfeel. Chardonnay wines were produced in 2014 with AF and MLF inoculated for simultaneous or sequential fermentations, and temperatures 15 and 21°C, with or without the addition of T. delbrueckii. Mouthfeel attributes of the wines produced were assessed by a winemaker panel, using Napping® and Ultra-flash profiling. Significant differences in mouthfeel perception were found based on timing and inoculation conditions, as well as between temperatures. Treatment type and temperature also effected the chemical composition of finished wines. Additionally, there are many interactions that occur between taste and aroma that may impact mouthfeel perception. This led us to investigate whether the aroma fraction of Chardonnay wine should be considered when investigating relationships between chemical composition and sensory perception of mouthfeel. Chardonnay wines were determined to have mouthfeel differences by altering the fermentation temperature of the alcoholic and malolactic fermentation as well as the timing of MLF and the presence of a non-Saccharomyces yeast during AF. Napping® and Ultra-flash-profiling were conducted using a panel of white winemakers. Each procedure was conducted twice: once with retro-nasal aroma and once without retronasal aroma. Napping® results showed that retronasal aroma impacted mouthfeel perception. Ultra-flash profiling displayed similar descriptive terms used with and without retronasal aroma, but terms were not consistently used for the same wine treatments with and without retronasal aroma. It is unclear if these differences are due to interactions or due to associated learning. These results suggest that for some mouthfeel terms the volatile fraction is playing a role and to establish relationships with chemical composition and mouthfeel perception it is important to consider both the volatile and nonvolatile wine fractions. We then investigated the impact of pre-fermentation juice treatments on mouthfeel characteristics of Chardonnay wine. Chardonnay grapes were harvested from Oregon State University’s vineyard in September, 2015. After destemming and pressing the juice was subjected to various treatments. These treatments included high, medium, and low turbidity level, as well as hyper-oxidation, two-hour skin contact, and two-hour skin contact + hyper-oxidation. All treatments went through alcoholic and malolactic fermentations. Total phenolics and hydroxycinnamic acids differed between skin contact and hyper-oxidation treatments. Wines that underwent hyper-oxidation contained the lowest total phenolics. Hyper-oxidation following skin contact reduced total phenolics but retained more than the hyper-oxidation treatment. Sensory analysis using citation by frequency procedure showed that all treatments modified the mouthfeel of finished wines. However, chemical analysis did not fully elucidate the cause of these differences. Pre-fermentation juice treatments can be utilized to develop stylistic differences in finished Chardonnay wine. The combined findings of this research demonstrate the usefulness of various enological practices to influence the sensory qualities of a Chardonnay wine, as well as emphasizing the importance of retro-nasal aroma’s influence on the mouthfeel experience of Chardonnay wine.

Download or read book The Sensory and Chemical Properties of Wines as Influenced by the Presence of Different Wine Bacteria and Yeasts written by Victoria Dawn Paup and published by . This book was released on 2021 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wine quality is a complex concept that is greatly influenced by its sensory characteristics and chemical composition, and many factors can contribute or detract from quality. The overall objective of this dissertation was to examine microbiological factors and their influence on wine quality using sensory evaluation and analytical testing methods. In the first study, the ability of the electronic tongue and experienced sensory panelists to discriminate among wines inoculated with spoilage microorganisms over storage was evaluated. Merlot wine was inoculated with spoilage microorganisms, in particular Brettanomyces bruxellensis, Pediococcus parvulus, Acetobacter pasteurianus, and Lactobacillus brevis, and tested weekly. Results showed that the electronic tongue discriminated among the inoculated wine samples starting at Day 21 of storage, while the experienced sensory panelists were unable to discriminate until Day 28. Therefore, the electronic tongue was demonstrated to be a useful tool for early detection of wine faults. In the second study, the influence of storage on the sensory and chemical characteristics of wines made with pectinase-producing non-Saccharomyces yeasts (NSY). The addition of NSY in Merlot wine increased cherry flavor over storage (p 9́Þ 0.05), an attribute often associated with wine quality. Additionally, significant differences were observed in pH and glycerol concentration in the wine. Some NSY that produce pectinase have been shown to increase polysaccharide concentrations which can improve mouthfeel characteristics. Building on this, providing sufficient substrate (pectin) may increase the activity of this enzyme. Therefore, the final study evaluated the influence of pectinase producing NSY on the sensory and chemical characteristics of wined with varying amounts of pectin. In both red and white wine, significant differences (p 9́Þ 0.05) were observed in the chemical parameters, in particular pH and D-galacturonic acid; however minimal differences were found in the sensory characteristics. Overall, this research advanced the understanding of how wine quality is affected by different wine microorganisms. In particular, new sensory and analytical methods for more rapid wine fault detection were developed, and a deeper understanding of the potential utilization of pectinase producing NSY to elicit chemical and sensory change was found.

Download or read book Influence of Sensory and Non sensory Attributes of Chardonnay Wine on Acceptance and Purchase Intent written by Jane Marie Yegge and published by . This book was released on 2001 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Wine Components on the Chemical and Sensory Quality of Wines written by Charles Diako and published by . This book was released on 2016 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wine is an alcoholic beverage containing numerous compounds that contribute to its overall quality. The overall objective of this dissertation was to examine the influence of matrix interactions in commercial red wines on the sensory and chemical properties of wines, and explore advanced methods of mathematical analyses of these data. In the first study, the influence of these matrix components and their interactions on wine quality was examined. Commercial Merlot wines (n=61) were evaluated for wine chemistry parameters, with the matrix components of interest identified as alcohol, tannin and mannoproteins. Sensory evaluation results showed complex interactions among tannins, alcohol and mannoproteins on the perception of most aromas, flavors, tastes and mouthfeel attributes (p0.05). Since human subjects vary in their sensory perceptions, panel reproducibility and precision was addressed. Panelists' variation in attribute evaluations was conceptualized as a linear operator called a bias matrix for feedback calibration and correction of panelists' evaluations. Results showed that the bias matrix corrected the panelist ratings of the samples, leading to higher reproducibility and precision. No significant differences (p0.05) were found between the original and corrected means. Predictive filtering showed that the panelists' corrected means for the attributes were closer to the predicted panel mean compared to their unfiltered means. The application of the electronic tongue for the assessment of wine quality was further explored. Strong correlations (r2>0.930) were reported between the electronic tongue and the sensory perceptions of sweet, sour, bitter, burning, astringent and metallic. Further research on the application of the electronic tongue to discriminate among wines and building predictive models was performed. Non-linear methods showed high discrimination among the commercial wines (90.1%), with high prediction accuracy of the electronic tongue output using the chemical parameters ([greater than/equal to sign] 90.0%). These results showed the dependence of the intensity of the electronic tongue signal on the chemical components of the wines. This dissertation demonstrated how wine matrix components influenced perception through suppression and enhancement of various sensory attributes. In addition, advanced methods of chemical and sensory data analysis were developed and validated. Results from this study will be useful for winemakers for wine quality optimization.

Download or read book Sensory and Chemical Evaluation of Riesling Chardonnay and Pinot Noir Fermented by Different Strains of Saccharomyces Cerevisiae written by Ann Dumont and published by . This book was released on 1994 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fermentation of the grape must into wine is one of the most important steps in winemaking. Selected yeast strains of Saccharomyces cerevisiae have been used for many years to ensure complete and even fermentations. The formation of volatile compounds also occurs during fermentation and will influence the sensory perception of the wine. The main objective of the research was to study the sensory and chemical composition of 1992 Oregon Riesling, Chardonnay and Pinot Noir wines fermented with different commercial S.cerevisiae strains. In the first study, Free-Choice Profiling was used to study the sensory profiles of all three varieties after 7 and 20 months of aging. This method was used in order to utilize a panel of expert winemakers for the tastings. The sensory data analyzed through Generalized Procrustes Analysis showed that some strains were similar while others were different in terms of aroma and flavor at 7 months of age. After 20 months of aging, differences and similarities were still present although the sensory profiles were different from the young wines. This last finding showed that differences are still present after a period of aging. In the second study, the chemical composition of all three varieties and the volatile composition of selected wines of Riesling and Chardonnay were studied. In both white varieties, statistical differences in titratable acidity, residual sugar, volatile acidity and malate content resulted from fermentation with different yeast strains. The volatile composition was qualitatively similar, but some quantitative differences, as relative concentration, were found. Whether or not those differences had a sensory impact was not investigated. Results of the present study showed the need for further studies in order to understand the role of yeast in flavor development. Relationships between sensory profiles and volatile composition could help winemakers to understand the influence of a selected strain on a particular variety and to select yeast strains to optimize wine quality.

Download or read book Sensory and Chemical Effects of Cross Flow Filtration and Pumping on White and Red Wines written by Peter Andrew Buffon and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the world of modern vinification, cross flow filtration and pumping are widely used. In the absence of systematic studies examining the effects of these unit operations on the resulting wine, winemakers are sometimes reluctant to use them to process their wines. Because cross flow filtration can not be accomplished without pumping, both of these unit operations were studied . Cross flow filtration is an increasingly common post-fermentation process in the wine industry. Because of the nature of the membranes used in this process, our hypothesis was that cross flow filtration would not have a significant impact on the sensory or chemical properties of either white or red wines. To investigate this, a California white wine blend and a California red wine blend were filtered in three 570 L lots using a Bucher Vaslin cross flow unit with a nominal 0.22 micron polyethersulfone membrane. The unfiltered control was sent directly to the bottling line without filtration. Panelists evaluated the wines nine times during an eight-month descriptive analysis panel with replicated tasting at each time point. UV-VIS spectrophotometry and the Adams-Harbertson assay were used to determine color and phenolic content of the filtered and unfiltered wines respectively. The effect of filtration was found to be significant for one sensory attribute out of 16 total measured in the white wine. Similar analysis for the red wines indicated that six sensory attributes were significantly different out of 16 total in the red wine. Unfiltered red wines were found to be higher in earthy, grassy, oak, and smoke aromas compared to filtered wines and lower in mixed berry and stone fruit aromas compared to the filtered wines, but only after two months in bottle. Cross flow filtration was found to have a stabilizing effect on the sensory profile of both wines. For both red and white wines, there were significant changes in color and phenolic profile with filtration, but it is not clear, especially for red wines, that the changes in phenolic compound concentration were large enough to be detected sensorially.The transfer of must, juice, and wine is a necessary process in vinification at various points from grape receiving through bottling. Pumps are among the most important pieces of equipment used to move wine from one place to another in commercial wineries. However, there has been a general lack of systematic data generated to assess the effect of pumping on the chemical and sensory properties of wine. These effects, if found, could be due to oxygen pickup during pumping, or some other mechanism of converting mechanical energy to changes in wine composition. To investigate this, a white wine blend and a red wine blend were pumped through a closed loop system at two different run times. Three different pumps were used in the experiment, a centrifugal pump, a flexible impeller pump, and a progressive cavity pump. This resulted in six treatments each for the white and red wines. The entire experiment was carried out in duplicate. A full sensory descriptive analysis panel was conducted on the wines using a ballot-trained panel. UV-VIS spectrophotometery and the Adams-Harbertson assay were used to determine color and phenolic content of the pumped and unpumped wines, respectively. Panelists were not able to differentiate pumped wines from the control, and additionally progressive cavity, flexible impeller, or centrifugal pumped wines from each other. Although statistically significant color differences were found between red wine treatments, these differences were less than 2% and no statistically significant phenolic differences were observed. Oxygen pickup was observed in the progressive cavity pump treatment, but relatively little was observed in the flexible impeller or centrifugal pump treatments. In summary, pumping caused little to no chemical or sensory changes in the experimental wines.

Download or read book Instrumental and Sensory Evaluation of Red Wine Astringency written by Scott Clifford Frost and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The presented work aimed to explore the chemical and sensory relationship of red wine astringency. Two sets of experimental Merlot wines were utilized. The first set of wines were produced at the Washington State University Irrigated Agriculture Research and Extension Center (WSU-IAREC), then sent to UC Davis for chemical and sensory analysis. This set of wines employed a factorial design to evaluate the relationship of tannin, acid, and ethanol concentration on astringent perception. The factorial design allowed for evaluation of the effect of each factor on the response variable. Descriptive analysis (DA) and temporal dominance of sensation (TDS) were used to describe the sensory response. A five-factor analysis of covariance (ANCOVA) was applied to the DA data. The results showed significant effect of tannin and acid concentration, but ethanol concentration was not a significant effect. The analysis of the TDS data was dictated by the ANCOVA results. TDS curves were constructed by factor level only for significant effects as shown by the ANCOVA. The use of a factorial design for the analysis of TDS data was novel. These results are contained in chapter 2. The second set of experimental wines were produced at The UC Davis Teaching and Research Winery. These wines focused on altering chemistry and sensory through winemaking. Nine cap management and extended maceration treatments were evaluated. Extended maceration was applied to c.v Merlot grapes for 1, 2, 4, 6, and 8 weeks. In addition, a punch down treatment and two submerged cap treatments were also evaluated. The treatment effects were characterized using descriptive analysis, polyphenol measures, basic wine parameters, and volatile analysis. Length of extended maceration defined the astringent texture of the resulting wines, while bitter taste and pepper spice aroma were defined by the type of cap management. The chemical and sensory results relating to winemaking are presented in chapter 3. The fourth chapter explores the relationship of descriptive analysis and temporal dominance of sensation. The DA and TDS results from the maceration experiment are utilized to compare and contrast the two sensory techniques. Similar results were shown between the DA and TDS results for “hot” taste, but maximum dominance rate for astringency and bitter were not correlated with maximum DA intensity. In addition, correspondence analysis was applied to the TDS frequency table in order to project the results into a multivariate space.

Download or read book Bentonite Fining During Different White Winemaking Stages written by Eugenio Cristian Lira Miranda and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis shows the results obtained from adding bentonite at different stages of the alcoholic fermentation in protein stability and reducing the bentonite required to reach stability. Results reflect the effect of this practice on alcoholic fermentation, chemical composition of wines, protein content and profile, aromatic profile and foam quality. The study was carried at pilot and industrial scale, with several grape varieties, in different geographical areas and during three vintages. The advantage of using bentonite during alcoholic fermentation was established, especially in moderate doses, making the addition from the middle of fermentation, obtaining more stable wines with less bentonite. Wines that were stabilized by bentonite treatment during fermentation were the best sensorial evaluated. Reproducibility between scales was confirmed for almost every parameter checked. Protein fractions and bentonite stabilizing dose for the different white wines was also identified and correlated. A commonly used technique was improved, achieving better quality wines.