Blended Wines Research Articles

Research on white and red wine blending in the production of rosé wines by means of the partial least squares method

AbstractThe difficult problem of recognizing wine blends in rosé wines is assessed using a powerful statistical method called partial least squares. Genuine rosé wines are first detected using a 280 nm/320 nm spectrophometric ratio. Blends of white and red wine are used as a calibration set and for an evaluation set of known composition. The proposed method evaluates the respective percentage of red and white wine in a blend and the error associated with the prediction. A comparison is made with principal component regression.

Computer‐aided Optimization of Wine Blending

ABSTRACTAn objective method was developed to blend wines for standardizing flavor quality. Aroma volatiles of varietal and white stock wines, and the target wine were analyzed by equilibrium gas headspace chromatography. Similarity of the aroma profiles of the varietal and stock wines to the target wine was calculated from GC peak areas. The simplex optimization program carried out computational bleeding to determine the ratios of the varietal and white stock wines that would be required to simulate the aroma of the target wine. For two blending experiments, the computer optimized blend could not be differentiated from target wine by a sensory taste panel.

Sensory and Chemical Analyses of Missouri Seyval blanc Wines

Sixteen Missouri Seyval blanc wines were evaluated by standard chemical and sensory analyses. Nine judges rated the intensities of fruity, vegetative, caramelized, pungent, musty and oxidized aromas, color, astringent and alcoholic flavors by mouth in Seyval blanc and blended wines. Free SO₂, total SO₂, volatile and titratable acidity, pH, color, phenol and ethanol were chemically determined for the Seyval blanc wines. Results were analyzed by analysis of variance with differences found across all wines for all variables except musty aroma. Principal component analysis (PCA) was performed on sensory data. The largest difference was a contrast of fruity with vegetative and oxidized aromas. Seyval blanc wines from the Hermann area were more fruity than wines from other areas. The second and third axes separated the wines based on vintage. The older wines were higher in caramelized aroma and golden color.

International colloquium on wines and wine blending, Aix en provence, France, 4 June 1987

International colloquium on wines and wine blending, Aix en provence, France, 4 June 1987

Effect of Sugar on Acid Perception in Wine

The ameliorating effect of sugar on acid perception was studied in a model system, a white wine, and a red wine. The range of acidity (0.47-1.20%) used was typical of that found in wines made from <i>V. vinifera</i> grapes; range of sugar content was 0-20%. Of the 35-40 tasters used on the model system, 20 were selected to continue the study in wine. A forced-choice paired-comparison random design was used throughout the study. Added sugar reduced the apparent acid taste in both the model system and the wines. A mean value of percent sugar needed to cause a 50% correct response level was determined for several concentrations of acid. A linear relationship (P&lt;0.01) was found between the mean value of sugar and the difference in the acid level used for its determination as compared with the acid level in the control. Although research has indicated a masking interaction between sugar and acid, such work has been concerned with threshhold or low levels (below 0.3g/100 ml) of acid rather than within the range normally found in acid foods. Also, only trends were observed rather than quantitative measures made of the masking effect. Pangborn (8,9), in studying the effects of suprathreshold amounts of sugars and organic acids, found a relation between decreasing apparent sweetness or acidity and increasing additions of acid or sugar at high levels of the added substance. Berg et al. (3) found a similar effect in testing the interaction of sugar and acid in an aqueous solution. Hinreiner et al. continued the work on sugar-acid interrelationships in aqueous solutions (4) and also in a white wine (5). Their data indicated adding sucrose had little effect on acid perception in wine. Pangborn et al. (10) made a similar observation with white wine. The climate in the grape-growing areas of the state of Washington develops a tart fruit which yields wines of high acidity. Kliewer and Lider (6) have shown that where <i>V. vinifera</i> grapes ripen at colder temperatures the acid content is frequently higher than is desirable. This is true with the wines produced from grapes grown in the Columbia Basin near Prosser. Since, as Amerine and Ough (1) have shown, consumer taste panels prefer a sweet wine to a dry wine, it was thought added sucrose could increase the acceptability of high-acid Washington wines. Such an amelioration of acid taste by sugar must first be shown to be measurable. Secondly, it would be advantageous to establish a quantitative relation which could guide the blending of wines. Finally, the modification should be demonstrated as advantageous in terms of acceptability. This study was done to try to quantify the effect of sucrose on the perception of acid in a model system, a white wine, and a red wine, using ranges of acid commonly found in wines of this type.

Malo-Lactic Fermentation

This chapter discusses the biochemistry and metabolism of bacteria causing malo-lactic fermentation, and also the application of this knowledge to control malo-lactic fermentation. Malo-lactic fermentation is necessary not only to deacidify some wines and to stabilize others, but also to improve some wines apparently by addition of certain products of metabolism, which make the flavor more complex. Natural malo-lactic fermentation can be encouraged by use of low levels of sulfur dioxide (less than 50 mg./liter), delay in addition of acidifying or fining agents, and storage at warmer temperatures. Aeration can stimulate malo-lactic fermentation. Malo-lactic fermentation is most likely to occur under conditions, which also favor wine spoilage. It is nearly impossible to obtain malo-lactic fermentation in wines with very high acidity -approaching pH 3.0. In regions producing these wines, it is often legal to increase the pH by addition of chemicals, by amelioration with water, or by ion exchange. Further, deacidification can then be made by malo-lactic fermentation. Increase in pH can also be obtained by blending the wine with another wine, which has undergone malo-lactic fermentation and has less acidity. The pH of the blended wine may then allow further malo-lactic fermentation.

Complexity of Flavor and Blending of Wines

SUMMARYThirty‐four pairs of similar, commercially acceptable wines and a freshly prepared 50–50 blend of each pair were scored for quality by a small expert panel. The composite scores of the blends did not differ to even a low degree of significance from the score of the highest‐scoring member of the pair. The scores of the blends were very highly significantly better than the scores for the low‐scoring wines or the mean of the low‐ and high‐scoring wine in each pair. In 7 cases among the 34 the blend's composite score was higher than that of the highest‐scoring wine, and in no case was it lower than that of lowest‐scoring wine of the pair. Increased complexity of flavor is believed to be a major factor in the favorable effect of blending shown in this study; other possible effects are discussed.