The Chardonnay turned brown primarily because of the exposure to oxygen. Oxygen can have a significant impact on the color and flavor of wine, and Chardonnay, being a white wine, is particularly susceptible to oxidation.
When wine is exposed to oxygen, it undergoes a chemical reaction called oxidation. This reaction can cause changes in the wine’s color, aroma, and taste. In the case of Chardonnay, oxidation can lead to the browning of the wine.
One of the main compounds in wine that is responsible for its color is phenolics. Phenolics are a group of chemical compounds that include tannins, anthocyanins, and flavonoids. These compounds contribute to the color, flavor, and mouthfeel of the wine.
However, when phenolics are exposed to oxygen, they can react and form new compounds that result in the brown coloration. This process is known as enzymatic browning. It is similar to what happens when fruits or vegetables turn brown when exposed to air.
The presence of oxygen inside the bottle can come from various sources. One possible source is faulty corks. If the cork is not airtight, it can allow oxygen to seep into the bottle, accelerating the oxidation process. This is why it is essential to use high-quality corks and ensure proper storage conditions to minimize oxygen exposure.
Additionally, the winemaking process itself can introduce some oxygen into the wine. During fermentation and aging, wine is often exposed to air through various steps, such as racking or barrel aging. While winemakers try to minimize oxygen contact during these processes, some exposure is inevitable.
It’s important to note that not all brown coloration in Chardonnay is necessarily a result of oxidation. Some Chardonnays, particularly those made with extended skin contact or aged in oak barrels, can develop a golden or amber color naturally. This is often considered desirable and contributes to the wine’s complexity and flavor profile.
The browning of Chardonnay is primarily caused by the oxidation of phenolic compounds in the wine. Oxygen exposure, whether through faulty corks or winemaking processes, can lead to enzymatic browning and the undesirable color change. Proper storage and handling techniques can help minimize the impact of oxidation and preserve the wine’s freshness and quality.