Left out in the cold: Serving wines chilled

Abstract

I like wine. In fact, when I initiated my doctoral studies, it was with the intention of becoming a winemaker. However, as a graduate student, I became less interested in how to make wine and more interested in the varied sensory experiences evoked by wines. Identical grapes grown in different environmental conditions can generate wines having very different sensory profiles. Similarly, the specific processing techniques a winemaker uses to create the wine will also greatly impact the product’s sensory attributes. In fact, there are numerous factors that influence a wine’s sensory profile and hence, its perceived quality. Of particular interest to the readership of Temperature is the effect of storage and serving temperature on the perception and liking of wine. Storage and serving temperatures of wine serve different purposes. Ideal storage temperature, for both red and white wine, is about 13°C and allows for maturation while minimizing the risk of premature aging. Incidentally, 13°C reflects the nearly constant temperature observed in historic wine caves of France. Serving temperature, however, has evolved to optimize the sensory experience associated with wine consumption. For red wines, optimal serving temperatures are suggested to be 15–18°C, slightly below room temperature. For most whites and rosés, optimal serving temperature is 4–10°C, slightly above refrigeration temperature. See Box 1 for recommendations on storing and serving wine. With the warm summer months receding, many wine consumers are opting for temperate red wines instead of the chilled white wines. During the hot summer months, chilled white wines have cooling and thirst-quenching properties that many people find desirable. However, chilling also has profound effects on the sensory properties of the wine and what consumers actually perceive during consumption. Specifically, cooling a food or beverage reduces the release of volatile compounds that make up the characteristic “nose” and “flavor” of the particular product. In the case of wines, volatile, aromatic compounds are inhaled through the nose to produce the aromas that characterize particular grape varietals, regions, or treatments (e.g. aging in oak barrels). The wine descriptors are often defined in terms of associated sensory experiences, such as tropical fruit (e.g. banana) or floral (e.g. orange blossom) notes in the case of white wines, and berry (e.g. blackcurrant) and herbaceous (e.g. bell pepper) notes for red wines. Additional attributes characteristic of different wines have been identified and delineated in seminal work from Prof. Ann Noble in the development of the wine aroma wheel [1]. When consumed, the volatile compounds first enter the oral cavity where, upon swishing and swallowing the wine, they are pumped up the back of the throat, through the nasopharynx to the olfactory epithelium in the nasal cavity to elicit retronasal flavor perceptions. Although colloquially referred to as “taste”, these retronasal flavor sensations are highly important to the enjoyment of food and beverages. This is best demonstrated when considering how the sensory profiles are significantly altered when the nose is plugged, for instance when sick with a cold or when pinching the nostrils shut. Water-air and/or ethanol-air partition coefficients reflect the solubility of aroma compounds in each of these media and describe the propensity of volatile molecules to escape from the beverage into the headspace above the liquid. Partition coefficients are temperature dependent; as wine is chilled, the kinetic energy of aroma molecules is reduced, thus leading to fewer aroma compounds in the headspace. Such an effect will reduce the overall intensity of the perceived aroma and flavor compared to when that same wine is evaluated at room temperature. Moreover, temperature has a differential effect on the partition coefficients of different compounds. Consequently, the chemical fingerprint – the concentration of the various volatile molecules relative TEMPERATURE 2019, VOL. 6, NO. 1, 1–3 https://doi.org/10.1080/23328940.2018.1563443