When to Drink Wine: Adjusting Forecasts for Your Cellar

Knowing when to drink wine starts with a drinking window, but that window is only a forecast. Your bottle's unique storage history determines whether the forecast applies. Some wines are only labeled with a vintage in better-than-average years, to maintain quality and reputation. The vast majority are produced to be drunk young and fresh. Excessive storage temperatures will have a marked effect on the shelf life of bottled wine. Marais (1986) observed faulty flavors and decreasing overall quality after 12 months' storage at 30°C. Ough (1986) states that temperatures exceeding 40°C induce visual and sensory changes in a matter of days. Ough (1992) advises that "In general, any storage place where the temperature exceeds 25°C for long periods and 40°C for short periods can affect wine quality." Amon and Simpson (1986) recommend storing bottled wine with the cork in contact with the wine. The location should be cool (15-20°C) and dry. Light exposure also contributes to degradation. Dozon and Noble (1989) found that white wines in clear glass developed "lightstruck" flavor significantly faster than those in green glass. Your bottle's journey and resting place are crucial factors in determining when to drink wine. They often override general vintage assessments.

What is a drinking window, and who sets it?

A drinking window is the period when a wine should be at its best. Its vintage and the region's characteristics often imply that period. Wines of superior vintages from prestigious producers and regions will often command much higher prices than those from average vintages. That is especially true if they are likely to improve further with some age in the bottle. Some wines are only labeled with a vintage in better-than-average years to maintain their quality and reputation. However, the vast majority of wines are produced to be drunk young and fresh. For example, Bordeaux AOC wines are produced in a style meant to be drunk young. Red Graves and Médoc wines, often dominated by Cabernet Sauvignon, are concentrated, tannic and long-lived. Most are meant to be cellared before drinking. The importance assigned to vintage is both varied and disputed. New York Times wine columnist Frank J. Prial declared the vintage chart to be dead, writing that "winemakers of the world have rendered the vintage chart obsolete."

How does storage temperature affect a wine's readiness?

Excessive storage temperatures accelerate a wine's aging process and can lead to significant degradation. The Australian Wine Research Institute (AWRI) Technical Note TN09 highlights that excessive storage temperatures will have a marked effect on the shelf life of bottled wine. Marais (1986) observed the development of faulty flavors and decreasing overall quality after 12 months' storage of wine at 30°C. AWRI Technical Note TN09 cites that finding. Temperatures exceeding 40°C will induce visual and sensory changes to a wine in only a matter of days, as stated by Ough (1986). Ough (1992) provides a general guideline: "In general, any storage place where the temperature exceeds 25°C for long periods and 40°C for short periods can affect wine quality."

Amon and Simpson (1986) recommend storing bottled wine with the cork in contact with the wine. The location should be cool (15-20°C) and dry. Exposure to temperatures significantly greater than ambient temperature may result in leakage of wine, according to AWRI Technical Note TN09. Thermal expansion may also move the cork stoppers. Such physical damage does not necessarily imply that the quality of the wine has also been affected. But it will obviously affect the appearance and marketability of the wine. Determining whether damage has occurred requires physical, chemical, and sensory tests. Those tests compare exposed bottles to bottles of the same wine that have not had such exposure.

The AWRI also notes that prolonged storage of wine in a refrigerator could adversely affect wine quality. It cites arguments that vibrations from the refrigerator's compressor are detrimental during wine storage. However, the Institute has been unable to find any literature on this specific subject. For more on protecting your collection, explore our guide on how to store wine.

What role does light play in wine aging?

Light exposure can lead to the development of undesirable "lightstruck" flavors and exacerbate copper instability in white wines. Maujean and Seguin (1983) demonstrated that "lightstruck" flavor (goûts de lumière) is due to the formation of volatile sulfur compounds. Those compounds are believed to derive from sulfur-containing amino acids such as methionine and cysteine. Riboflavin (vitamin B2) is present in low levels in musts and wines. It undergoes photo-activation and subsequent reduction when exposed to light, according to AWRI Technical Note TN09. The wavelengths involved are 370 nm and 440 nm. This process can lead to the oxidation of sulfur-containing amino acids. That in turn forms the sulfur compounds responsible for the sensory off-character.

A study by Dozon and Noble (1989) exposed still and sparkling white wines, bottled in green glass, to light from fluorescent lamps. That exposure produced lightstruck flavor. The intensity of the flavor was statistically significant in the still and sparkling wines. That took exposure for 31.1 hours and 18 hours, respectively. In comparison, the same wines stored in clear glass developed a statistically significant level of the off-flavor after exposure for only 3.3 hours and 3.4 hours, respectively. Sensory assessment of the affected wines indicated a decrease in "citrus" aromas and an increase in "cooked cabbage," "corn," "wet wool/wet dog," and "soy/marmite" aromas. AWRI Technical Note TN09 reports that these trials involved placing wines 35 cm from two 40-watt fluorescent lamps.

The intensity of light sources also matters. Gordon Watson, of Gordon Watson and Associates, notes the output of a 36 W fluorescent lamp. At an illuminance of 400 lux it provides approximately 14 mW/m2 of UV-A radiation. UV-A radiation in full sunlight is 60,000 mW/m2. This means direct sunlight provides 4286 times the amount of UV-A radiation as fluorescent lamps. Retail window displays expose bottled wine to direct sunlight. That is likely more deleterious to wine quality than exposure to electric lighting systems.

Another negative aspect of light exposure is its potential to exacerbate copper instability in susceptible white wines. The AWRI has investigated cases of haze in white wine. Bottles stored on the uppermost layer of bins developed a haze. Underlying bottles did not. The Institute attributes this to copper instability. The Institute notes that white wines containing a concentration of copper greater than approximately 0.5 mg/L are likely to be susceptible to copper haze. If the level is greater than this arbitrary limit, protection from exposure to light will only delay the inevitable. Rankine (1989) indicates that amber glass is most effective in excluding wavelengths below about 450 nm. Marketing concerns, though, often dictate glass color.

Can vintage charts reliably predict when to drink wine?

The reliability of vintage charts is widely disputed, particularly for wines outside of specific regions like Bordeaux. Roman Weil is co-chairman of the Oenonomy Society of the US and a professor at the University of Chicago. He tested the hypothesis that experienced wine drinkers "cannot distinguish in blind tastings the wine of years rated high from those of years rated low, or, if they can, they do not agree with the vintage chart's preferences,". Weil used wines ranging from four to 17 years beyond their vintage with 240 wine drinkers. He found that tasters could not distinguish between wines of good and bad vintages, except for Bordeaux wines. Even when a distinction could be made for Bordeaux, the match between tasters' individual assessments and the charts' rankings was little better than tossing a coin. When replicated with wine experts, including French wine academics, the results were again the same as chance.

Despite these findings, Weil does not consider a vintage chart useless. He suggests using one to help "find good buys in wine," as wine made in years considered worse than average for vintages may be priced far below its actual quality. This perspective aligns with James Laube of Wine Spectator, who asserted that "even an average vintage can yield some grand wines." In Spain, wine regulators publish official classifications of each vintage, providing a formal assessment. However, a common Bordelais saying reminds us: "The best vintage is the vintage we have to sell." Understanding these nuances can help you navigate the fine wine market index more effectively.