Many wine enthusiasts find their cupboards filled with an extensive collection of wine glasses. Others may appreciate wine bars that serve wines in multiple glass types tailored to different wines.
The marketplace offers an extraordinary variety of wine glasses: Bordeaux glasses, Burgundy glasses, Riesling glasses, New World Pinot Noir glasses, and more. Each style exhibits distinct morphological characteristics. Manufacturing methods further diversify the selection, with hand-blown and machine-made variants available. In some cases, the distinguishing features between products remain unclear.
The question of whether glass-to-glass variation produces measurable effects has been a subject of ongoing debate.
Scope of Glass Influence
When rigorously examining whether glass affects the perception of wine aroma and flavor, the scope of investigation extends beyond shape alone. As discussed in “Does Wine Glass Selection Alter the Taste of Wine?“, comprehensive comparison of glasses in their totality is nearly impossible.
However, when focusing exclusively on glass shape, the extent of its influence on wine perception has been largely elucidated.
This article addresses the question of whether using different glass shapes enhances the enjoyment of wine aroma and flavor, providing answers grounded in scientific evidence.
Start by Closing Your Eyes
Influence of Visual Bias
To determine whether altering glass shape changes wine perception, we must first take a fundamental step: closing our eyes.
Experienced wine consumers, consciously or unconsciously, harbor certain fixed notions. Red wines are served in large glasses, white wines in smaller glasses with narrow rims, dessert wines conversely in wide-mouthed glasses, and sparkling wines in flute glasses. These “typical” glass-wine pairings have become established conventions in our minds.
All such preconceptions constitute cognitive bias.
Blind Tasting Verification Results
Controlled validation experiments have confirmed significant discrepancies between results from blind tastings—where subjects were literally blindfolded beforehand—and tastings of identical wine-glass combinations conducted without blindfolds. When subjects visually observed the glasses, sensory evaluation scores increased for pairings recognized as “appropriate,” while evaluation scores decreased for pairings perceived as “unconventional.” Furthermore, subjects used more descriptive vocabulary when describing wines they viewed in pairings they considered “appropriate.”
The influence of visual information and its associated cognitive bias is powerful, readily overriding the actual aromatic and gustatory impressions perceived by the nose and palate. To avoid such cognitive bias, wine must be evaluated with visual information eliminated. Ideally, subjects should not touch the glass. Human satisfaction levels vary based on tactile sensation and weight perceived when holding objects. Conversely, when using glasses while seeing them and holding them to discriminate, it becomes nearly impossible to understand the true effects based solely on shape differences.
Perception of Wine Aroma and Flavor
Aroma Perception Mechanism
How do humans perceive wine aroma and flavor? One might answer that we use the mouth and nose. While this is certainly correct, understanding changes slightly when connecting this perceptual process to glass shape.
Volatile aroma compounds contained in wine poured into a glass first volatilize from the liquid surface into the interior space of the glass, known as the headspace (gas phase). We detect these aroma compounds accumulated in the headspace by bringing our nose close to the glass.
Subsequently, by bringing the glass to our lips, we introduce wine into the oral cavity. We simultaneously sense taste through taste buds on the tongue while constructing an overall flavor perception through trigeminal nerve stimulation via temperature and tactile sensation.
Validity of Flow Pattern Theory
Many glass manufacturers explain that glass shape determines the flow pattern (inflow pattern into the oral cavity)—the volume and position of wine flowing into the mouth—thereby affecting flavor perception. However, flow pattern theory has recently been questioned. The flow pattern concept is predicated on the taste map theory, which posits that taste buds corresponding to each taste quality are distinctly distributed across the tongue surface.
Recent research negates the classical taste map theory, demonstrating that all taste qualities are perceived uniformly across the entire tongue surface. With the taste map discredited, the concept of emphasizing specific taste qualities through flow patterns becomes untenable.
Temperature Effects
Conversely, temperature effects remain substantial. Wine temperature directly influences trigeminal nerve stimulation during consumption and the volatility of aroma compounds within the glass. Additionally, temperature affects the types of retronasal aromas that travel from the oral cavity to the nasal cavity during swallowing. Since humans reportedly perceive much of taste-related aroma through retronasal olfaction, wine temperature constitutes an extremely important element when enjoying wine aroma and flavor.
Glass Creates Neither Aroma Nor Flavor
Only Concentration Changes Occur
When Glass A intensifies berry character while Glass B does not, one might conclude that glasses sometimes create aromas and flavors. This perception is erroneous.
Glass shape does not alter the types of aroma compounds contained in wine. What glass shape modifies is not the types but rather the concentration within the headspace. Regarding taste, it has been confirmed that glass shape has absolutely no effect except for acidity alone.
Multiple validation studies have confirmed that changing glass shape produces variations in perceived aroma intensity. This means that glasses of different shapes alter the concentration of individual aroma compounds in the headspace. Because concentration increases, humans perceive that aroma more intensely.
Surface Area and Aroma Intensity Are Unrelated
When told that headspace concentration changes, one might assume that volatility simply changes. This would suggest that larger glasses are superior. As glass size increases and fillable volume expands, bowl diameter enlarges. This increases the surface area of the wine’s liquid surface. Increased surface area should increase volatilization of aroma compounds and elevate headspace concentration. This reasoning appears logical. However, it is incorrect.
Validation studies have already confirmed no correlation between liquid surface area and aroma intensity. Similarly, simple glass volume is irrelevant. Larger glasses do not inherently produce stronger aromas. The claim that delicate red wine aromas should be enjoyed in large glasses amounts, according to experimental results, to unsubstantiated marketing copy.
Differentiating White Wine and Red Wine Glasses Is Meaningless
Volatile Compound Behavior Is Independent of Color Classification
No evidence suggests that glass shape differentially affects the volatility of aroma compounds in white wines versus red wines. Certainly, different volatile compounds volatilize at different temperatures. Therefore, differences in which volatile compounds predominate at specific temperature ranges may produce variations between white and red wines. However, if wines contain identical volatile compounds, no difference exists whether the wine is white or red.
In other words, using different glasses for white and red wines is meaningless. Fundamentally, a glass suitable for white wine is also suitable for red wine. The converse is equally true.
Bowl-to-Rim Ratio Is Critical
For both red and white wines, what matters is the ratio between the maximum bowl diameter and the rim diameter. Glasses with large bowl diameters and small rim diameters—those with tapered openings—have been shown to enhance perceived aroma intensity. The reason is straightforward: such morphology facilitates aroma compound accumulation in the headspace, promoting concentration increases.
Effect Magnitude Is Limited
Nevertheless, research has revealed that even this effect is not particularly substantial. Some controlled experiments that adjusted verification results to account for subjects’ olfactory sensitivity reported no significant differences among all compared glasses.
As numerous validation studies demonstrate, glass shape likely exerts far smaller influence on wine aroma and flavor perception than we commonly assume.
What Size Glass Is Appropriate?
Comparison with Standard Glasses
It has been confirmed that glasses with large bowl diameters and small rim diameters—those with tapered openings—facilitate relatively stronger aroma perception. However, research also reveals that indefinitely enlarging the bowl while maintaining a small rim does not yield proportionate benefits.
Several standard glasses exist for wine evaluation: the ISO standard glass (International Standardisation Organisation), the INAO standard glass (the French Institute National des Appellation d’Origine), and the DIN standard glass (Deutsche Industrie Norm). These glasses are employed to avoid evaluation variability caused by glass differences. ISO and INAO glasses are frequently used in international competition evaluations and research institutions.
Ratio Increases Have Limits
Compared to the ISO standard glass, Burgundy glasses with larger bowls and smaller rims exhibit stronger tendencies to intensify perceived aroma. However, while this difference was detected as statistically significant, it was simultaneously confirmed to be modest in magnitude.
The bowl-to-rim diameter ratio of the ISO standard glass is 1.47, while that of the Burgundy glass used in the aforementioned validation was 1.71. Despite substantial differences in these ratios, differences in aroma perception were not particularly pronounced. This indicates that simply increasing this ratio yields no additional benefit.
Summary: Is One Glass Sufficient?
Shape-Only Effects Are Limited
We have examined how little glass shape actually influences wine taste and aroma. Upon learning these findings, one’s carefully arranged collection of wine glasses might suddenly appear diminished in value. However, concern is unwarranted. There is no need yet to reorganize those glasses.
As we have seen, glass shape exerts far smaller influence on wine taste and aroma than we ordinarily perceive. However, these validations were conducted with blindfolded subjects who did not touch the glasses, in order to evaluate glass shape in isolation. Conversely, we do not consume wine blindfolded, having assistants bring glasses to our lips without touching them. We cannot escape the non-shape influences that glasses possess.
Importance of Non-Shape Elements
Additionally, when glass shape changes, wine movement during swirling differs. Temperature changes and aromatic compound volatility changes are implicated here. Furthermore, bowl size and morphology alter the perceived color of poured wine. Generally, larger bowls make wine color appear lighter. Humans possess characteristics such as perceiving sweetness in red hues. When visual information is incorporated, glass shape can substantially influence wine taste and aroma perception.
Three Evaluation Axes
When using wine glasses, humans generally evaluate them through a synthesis of three evaluation axes: sensory evaluation through olfaction and gustation, aesthetic perception evaluation based on visual appearance, and hedonic evaluation based on personal preference. If the objective is pure wine evaluation, one must consistently use the same “appropriate” glass to avoid evaluation axis variability. However, if the goal is to enjoy wine in its various dimensions, using multiple favorite glasses is the correct approach. Filling one’s cupboard with glasses is by no means erroneous.
