Excessive levels of diacetyl in wine can have a significant impact on the mouthfeel. Diacetyl is a naturally occurring compound that is produced during fermentation and aging, but when present in high concentrations, it can alter the overall sensory experience of the wine.
What is Diacetyl?
Diacetyl is a volatile compound that belongs to the group of diketones. It is often described as having a buttery or creamy aroma, reminiscent of buttered popcorn. In small amounts, diacetyl can contribute to the complexity and richness of a wine’s flavor profile, particularly in certain styles like Chardonnay. However, when present in excessive levels, diacetyl can become a sensory fault that negatively impacts the wine’s quality.
Impact on Mouthfeel
When a wine contains excessive levels of diacetyl, it can affect the mouthfeel in several ways:
- Buttery Texture: Diacetyl can impart a slick, buttery texture to the wine, coating the palate and masking other flavors. This sensation can be off-putting to some consumers, particularly those who prefer wines with a cleaner, crisper mouthfeel.
- Decreased Acidity: High levels of diacetyl can diminish the wine’s overall acidity, making it feel flabby or flat on the palate. Acidity is a crucial component of wine balance, and its reduction can result in a less vibrant and refreshing mouthfeel.
- Weight and Body: Diacetyl can contribute to a perception of increased weight and body in the wine, giving it a heavier, more viscous feel. While this characteristic may be desirable in certain styles of wine, an excess of diacetyl can throw off the wine’s overall balance and structure.
- Persistent Finish: Wines with high levels of diacetyl may leave a lingering, oily sensation in the mouth that detracts from the overall drinking experience. This prolonged finish can overshadow the wine’s other flavors and make it less enjoyable to consume.
Quality Implications
The presence of excessive diacetyl in wine is often considered a fault, as it can mask the true character of the wine and compromise its overall quality. Some of the key quality implications include:
- Loss of Typicity: Diacetyl can obscure the varietal characteristics and terroir-driven nuances of the wine, making it more difficult to discern its origin or grape variety.
- Diminished Complexity: The overpowering buttery notes of diacetyl can overwhelm the wine’s subtle aromas and flavors, reducing its complexity and depth.
- Detrimental Aging Potential: Wines with high levels of diacetyl may not age as gracefully as those without this fault. The buttery character can become more pronounced over time, leading to a less appealing sensory profile.
- Consumer Perception: Consumers may perceive wines with excessive diacetyl as flawed or unbalanced, resulting in lower ratings and decreased market appeal.
Prevention and Remediation
Winemakers can take several steps to prevent or remediate the presence of excessive diacetyl in wine:
- Monitoring Fermentation: Careful monitoring of fermentation conditions, including temperature control and yeast selection, can help minimize the production of diacetyl during the winemaking process.
- Malolactic Fermentation: Conducting malolactic fermentation under controlled conditions can help reduce diacetyl levels in wine by converting it to less detectable compounds.
- Barrel Aging: Barrel aging can help integrate and soften diacetyl in wine, particularly in styles where a subtle buttery character is desirable, such as certain Chardonnays.
- Filtering and Fining: Filtration and fining techniques can be employed to remove excess diacetyl from the wine before bottling, ensuring a cleaner and more balanced sensory profile.