What Does Sur Lie Aging Do to the Wine

What does sur lie aging do to the wine? One measurable effect is on how you must store the bottle afterwards. Some wines undergo lees aging, such as methode champenoise wines where yeast autolysis occurs. For those, a key consideration for long-term preservation is managing light exposure. The liberation of amino acids from yeast cells during autolysis can increase the concentration of sulfur-containing amino acids. The Australian Wine Research Institute (AWRI) notes as much (TN09). This elevated concentration may, in turn, heighten the wine's susceptibility to developing a 'lightstruck' flavor when exposed to light. Maujean and Seguin (1983) link that phenomenon to the formation of volatile sulfur compounds (TN09). Protecting these wines from light is therefore a critical step. It prevents the formation of undesirable off-flavors and maintains their intended quality.

Understanding how external storage conditions interact with the wine's composition is crucial for preserving its integrity. That matters most for fine wines like lees ageing in Champagnes we track (DP 8+ years on lees) intended for extended cellaring after purchase at auction.

How does temperature affect your wine's aging?

Temperature control is a critical factor in how your bottled wine ages and evolves. Excessive storage temperatures significantly reduce the shelf life of bottled wine. They lead to rapid aging and deterioration. Marais (1986) observed "the development of faulty flavours and decreasing overall quality after 12 months’ storage of wine at 30°C" (TN09). Temperatures "in excess of 40°C will induce visual and sensory changes to a wine in only a matter of days," according to Ough (1986) (TN09). The AWRI notes that "any storage place where the temperature exceeds 25°C for long periods and 40°C for short periods can affect wine quality" (Ough 1992, TN09). Robert Parker (2008) suggests that "somewhere between 10 and 25% of wines sold in the USA have been damaged due to exposure to extreme heat".

Avoid fluctuations in temperature, known as thermal cycling (Hirlam 2019a,b). Significant variations between day and night can cause "Leakage of wine and/or movement of cork stoppers due to thermal expansion of wine". This physical damage does not necessarily imply affected quality. It "will obviously affect the appearance, and therefore the marketability, of the wine". We also highlight that temperature control systems are important for stable cellar temperatures. Variations cause corks to expand and contract, which leads to oxidation.

Wine exposed to excessively cold temperatures "can freeze and expand, causing the cork to be pushed out or (more usually) the bottle to crack," which allows "more oxygen to be exposed to the wine". For optimal aging, a relatively cool and constant environment works best. Amon and Simpson (1986) recommend storing wine "in a cool (15-20°C), dry location" (TN09). Most experts, including Jancis Robinson, suggest constant temperatures "between 50 and 59 °F (10 and 15 °C". Tom Stevenson speculates that "52 °F (11 °C) may be the most ideal temperature for storage and aging," while Karen MacNeil recommends keeping wine intended for aging in a cool area with a constant temperature "around 55 °F (13 °C)". Wine can be stored "as high as 69 °F (21 °C) without long-term negative effect". Professor Cornelius Ough of the University of California, Davis believes that wine can be exposed "temperatures as high as 120 °F (49 °C) for a few hours and not be damaged".

Chanut et al. (2023) researched microagglomerated cork stoppers in miniaturized bottle systems with model wine. They showed that at 35°C, total oxygen transfer did not increase significantly for up to 9 months. However, "beyond this duration of storage, a significant transfer at the glass-cork interface started to occur". At 50°C, this shift occurred "within the first 3 months of storage". This increased oxygen transfer at higher temperatures could be due to "partial melting of the surface treatment agent" (paraffin and silicone) or a "modification of the mechanical properties of the cork". Understanding these impacts helps you protect your fine wine investment.

What role does light play in wine degradation?

Light exposure can significantly impact wine quality. The main route is the development of 'lightstruck' flavor. The AWRI states that light exposure "can affect the taste of a wine through the production of volatile sulfur compounds, known as ‘lightstruck’ flavour". Maujean and Seguin (1983) demonstrated that "flavour (goûts de lumière) is due to the formation of volatile sulfur compounds" (TN09). These compounds are believed to originate from sulfur-containing amino acids, methionine and cysteine. Riboflavin (vitamin B2) undergoes photo-activation when exposed to light at wavelengths of 370 nm and 440 nm (TN09).

Light-bodied white wines are particularly vulnerable. Dozon and Noble (1989) found that "exposure of still and sparkling white wines, bottled in green glass, to light emitted from fluorescent lamps resulted in the production of the lightstruck flavour" (TN09). The flavor intensity was "statistically significant in the still and sparkling wines after exposure for 31.1 hours and 18 hours, respectively" (TN09). For the same wines stored in clear glass, a "statistically significant level of the off flavour" developed much faster, after "only 3.3 hours and 3.4 hours, respectively" (TN09). Sensory assessment described a "decrease in ‘citrus’ aromas and an increase in ‘cooked cabbage’, ‘corn’, ‘wet wool/wet dog’ and ‘soy/marmite’ aromas" (TN09).

Direct sunlight poses a much greater risk than artificial lighting. Gordon Watson notes that direct sunlight provides "4286 times the amount of UV-A radiation as fluorescent lamps" (TN09). Therefore, "exposure of bottled wine to sunlight, as may be the case in retail window displays, will be more deleterious to wine quality than exposure to electric lighting systems" (TN09).

The color of your wine bottle offers some protection. "Light-bodied white wines run the greatest risk from light exposure, and for that reason, they are often packaged in tinted wine bottles that offer some protection from light". Wines in "clear, light green and blue colored bottles are the most vulnerable to light". Rankine (1989) indicates that "amber glass is most effective in excluding wavelengths below about 450 nm" (TN09). In your cellar, storing wines in "corrugated boxes or wooden crates" helps protect them from direct light.

Beyond flavor, light exposure can also "exacerbate copper instability in susceptible white wines" (AWRI, TN09). The AWRI recommends that white wines with "a concentration of copper greater than approximately 0.5 mg/L are likely to be susceptible to copper haze" (TN09).

Is humidity important for wine storage?

Maintaining appropriate humidity levels is essential for preserving your wine. That matters most for bottles sealed with natural corks. "Some degree of humidity is required in order to keep wines with cork enclosures from drying out". If a cork dries out, it "can allow oxygen to enter the bottle, filling the ullage space and possibly causing the wine to spoil or oxidize". Alexis Lichine contends that "low humidity can still be detrimental to premium wine quality due to the risk of the cork drying out".

However, excessive humidity also carries risks. It "can also pose the risk of damaging wine labels, which may hinder identification or hurt potential resale value".

The ideal humidity range remains open to debate. General recommendations still exist. Jancis Robinson notes that "75% humidity is often cited as ideal but also that there is very little significant research to definitively establish an optimal range". The Comité Champagne recommends that humidity "must be high and constant, between 60% and 80". Climate Controlled Wine Storage facilities typically maintain "moderate humidity levels (55%-75%)".

Humidity also affects the cork itself. Relative humidity "above 50% is required for good elasticity of cork-based closures," according to Lagorce-Tachon et al. (2016). Conversely, "a relative humidity above 80% has been found to increase risk of mildew formation on the outer surface of cork" (Jackson and Lombard 1993).

You should avoid storing wine in a refrigerator for long periods. Tom Stevenson recommends that wine "should not be kept in a refrigerator since the refrigeration process often includes dehumidifying, which can quickly dry out corks". For more on fill levels, consult our guide on wine ullage levels explained.

Does bottle orientation matter for corked wines?

The orientation of your wine bottles during storage is a factor to consider. Advice differs depending on the wine type. For most still wines sealed with corks, horizontal storage is traditionally recommended. Most wine racks are designed for this. The idea is that "the cork is more likely to stay moist and not dry out if it is kept in constant contact with the wine". Mas et al. (2002) found that "after 24 months wines stored upright had higher yellow/brown colour (measured by OD420nm absorbances) than those stored horizontally; however, the differences were not significant". Their study also "showed that oxidation was higher for upright samples sealed with agglomerated