White Wine Colour Age: What Changes Mean for Your Cellar

White wine colour ages along a predictable path. It runs from pale yellow or green hues to deeper gold, amber, or even brown, primarily due to oxidation. White wine colour, age, and fill level are the three things you can read before the cork comes out. This transformation can indicate a wine’s healthy maturation or, in extreme cases, spoilage. A lower fill level, known as ullage, often points to increased oxygen exposure, accelerating these colour changes. Factors like storage temperature and light exposure also play a significant role in how quickly and dramatically a white wine’s colour shifts. They offer clues about its condition before you even open the bottle. Understanding these visual cues can help you assess the health and potential drinkability of your aged white wines.

Why does white wine change colour as it ages?

White wine colour changes as it ages primarily due to oxidation. The Australian Wine Research Institute (AWRI) states that oxidation, particularly of white wines, was a common fault in Australian white wines 40 years ago. This oxidation can lead to a dulling of the aroma. It can also bring on the development of 'cardboard', 'straw', 'hay-like', 'sherry-like', or 'madeirised' aromas. In extreme cases, AWRI notes, a 'wet wool', 'wet dog', or 'varnish-like' aroma can be evident. Oxidation is also linked to browning in wines, according to AWRI.

Acetaldehyde is a compound whose levels increase as wines age, due to chemical oxidation of ethanol. AWRI reports that it can impart 'over-ripe bruised apples', 'stuck ferment', 'sherry', and 'nut-like' characters. That happens when its concentration exceeds 125 mg/L. These sensory changes are often accompanied by a deepening of the wine’s colour. Light exposure can also induce colour changes in wine, as referenced by Dias et al. in the Chanut et al. study. That study notes that green-coloured bottles offer greater protection than uncoloured bottles. They do not totally prevent light-induced colour change.

What is ullage and how does it relate to colour?

Ullage is also known as the fill level or headspace. WineBid defines it as the space at the top of a wine bottle not occupied by wine. It is the gap between the cork and the wine itself, according to Decanter. A low ullage can indicate seepage and oxidation of the wine, and affect its value considerably, WineBid states. The greater the amount of ullage, the more potential that the wine has been exposed to harmful levels of oxidation. This exposure to oxygen directly contributes to the colour changes observed in aged white wines.

Auction houses and retailers of mature wines pay close attention to ullage levels. Those levels feed into the resale value of the wine. Decanter notes that ullage is one of the key things wine buyers should look for, particularly in more mature vintages. Buyers for auction houses will pay close attention to it as part of their assessment of a wine's health. Matt Walls, DWWA regional chair for Rhône, told Decanter that ullage is "the best guide you have to the condition of a bottle of wine, especially if you don't know for certain how it's been stored." Bordeaux and Burgundy wines have distinct bottle shapes. WineBid note that ullage levels are described differently for each. For Burgundy, fill levels are measured in centimetres from the cork. For Bordeaux, they are described relative to the bottle's shoulder.

Here is a comparison of common ullage terms and their assessments:

Ullage Description (Bordeaux)	Ullage Description (Burgundy)	Age Considered Normal	Assessment (WineBid)	Assessment
Base of neck or higher	Two centimeters or less	Any age	Perfect fill level	Normal for young wines
Very top shoulder	Three centimeters	20+ years	Excellent fill level	Good condition for wines over 15 years
Top shoulder	Four centimeters	15+ years	Acceptable and normal fill level for wines 15 years and older; very good for wines 35 years and older	Normal for older wines; generally okay in older wines, especially those over 20 years
Mid shoulder	Five centimeters	40+ years	May be normal for a wine that is 40 years old or older	Possible oxidation; price should reflect the risk
Low shoulder	N/A	Older wines	Occurs in older wines	Extremely risky; possibly undrinkable

For more detailed information on fill levels, consult our guide on wine ullage levels explained.

How do storage conditions impact white wine colour?

Storage conditions, particularly temperature and humidity, significantly influence the rate of oxygen ingress and, consequently, the colour evolution of white wines. Decanter states that abnormally low fill levels indicate poor storage conditions, namely high temperature or low humidity. Long-term storage requires a temperature of around 13°-15°C and a humidity level of 70% or so, according to Decanter. It also requires an absence of light and vibration. Wines kept in lesser conditions will experience evaporation and diffusion at a faster rate. That leads to higher ullage levels and increased oxidation.

A study by Chanut et al. investigated the evolution of oxygen barrier properties of microagglomerated cork-based stoppers over 24 months under various storage conditions. The study found that the oxygen diffusion coefficient of the cork stopper alone was not modified by temperature, storage position, or the presence of model wine. The total oxygen transfer through the bottleneck-cork system was significantly impacted.

The presence of model wine increased the total oxygen diffusion coefficient from 2.3 × 10⁻¹¹ to 4.7 × 10⁻¹¹ m² s⁻¹ after three initial months of storage at 20°C. That temperature is considered ambient for bottles kept on shelves. This increase was attributed to the sorption of water and ethanol in the cork. That sorption can favour surface diffusion and modify the cork's mechanical properties, leading to increased oxygen transfer at the glass-cork interface. This interface accounted for nearly 70% of the total oxygen transfer in the presence of model wine, Chanut et al. reported.

Temperature also had a strong impact on oxygen transfer. At a storage temperature of 20°C, the oxygen barrier properties of the bottleneck-cork system remained unchanged over 24 months. Bottle shipping easily reaches 35°C. At that temperature, a significant transfer at the glass-cork interface started to occur beyond nine months of storage. At 50°C, this shift occurred within the first three months of storage. The total diffusion coefficient reached 7.2 × 10⁻⁶ m² s⁻¹ after six months, approaching the diffusion coefficient of oxygen in the air (2.0 × 10⁻⁵ m² s⁻¹). That indicates leakage at the glass-cork interface. This could be due to a partial melting of the paraffin and silicone coating on the stopper or a modification of the stopper's mechanical properties, Chanut et al. concluded.

The study also looked at the storage position of the bottle. That meant vertical (stopper in contact with the vapour phase) or horizontal (stopper in contact with the liquid phase). Position did not significantly influence oxygen transfer through the bottleneck-cork system.

Proper storage is crucial for preserving your wines. Learn more about optimal conditions in our guide on how to store wine.

What are the risks of colour change in aged white wines?

The most significant risk associated with undesirable colour change in aged white wines is oxidation. It can lead to spoilage and render the wine undrinkable. AWRI describes oxidation as a fault, particularly in white wines, leading to off-flavours and browning. Julia Sewell, sommelier at The Fat Duck, told Decanter that "age aside, ullage lower than midshoulder level poses a much higher risk of spoilage."

Matt Walls advises caution when buying older bottles. If the fill level is much below the bottom of the neck of a Bordeaux bottle, you should "think twice before buying it," echoing Christie's analysis, as reported by Decanter. David Dudley-Jones of Dudley Jones Fine Wines stated in Decanter magazine 2016 that lower fill levels and resultant seepage usually point to heat exposure and poor storage.

While colour change and ullage are strong indicators, they are not foolproof. Walls noted that you "do sometimes come across old bottles with a very low fill that have remained in good nick." Sewell added that "the clues can only be confirmed once the wine is tasted."

To minimise risks when acquiring aged white wines, Dirceu Vianna Junior MW advises establishing the provenance of the bottle. Decanter suggests several methods for assessing a wine's condition without pulling the cork. You can shine a strong light at the punt to check for sediment and abnormal loss of colour. You can cut the capsule to inspect the cork and check for seepage. You can also touch the cork gently to make sure it does not move.

Understanding the implications of colour change is particularly important for wines susceptible to premature oxidation, such as aged white Burgundy (Meursault, Corton-Charlemagne) and the premox colour tell. When buying at auction, these visual cues are vital for informed decisions. Explore more about making smart purchases in our guide on how to buy wine at auction.

To ensure you open your wines at their peak, access our drink-window data for your cellar.