Have you heard of a white wine take on a pinkish tint? That’s the curious phenomenon known as “pinking.” White wines are celebrated for their crisp and clear appearance, but pinking introduces a rosy hue that’s not supposed to be there. This colour anomaly can crop up during winemaking or after the wine is bottled, causing concerns for both winemakers and wine enthusiasts. It has been shown that white wines that have been made in a highly reductive way, for example New Zealand Sauvignon blanc, can sometimes develop a pink colour on exposure to air.
There are a couple of methods to detect and quantify pinking’s presence. One approach employs a spectrophotometer, a device that gauges how light is absorbed by the wine at specific wavelengths. By doing so, you can determine if anthocyanins are present and to what extent they contribute to the pink tint.
Another technique features a colorimeter, a tool that assesses the wine’s colour changes based on different colour properties. This provides a numerical value reflecting the degree of colour shift, essentially quantifying the pinking process.
Yet, numbers aren’t the only indicators. Sensory analysis is also important. Visually inspecting the wine is a reliable tool to evaluate pinking’s presence.
To curb pinking, winemakers can adopt preventive measures. These include minimizing contact between grape skins and juice, as anthocyanins reside mainly in the skin. Additionally, controlling sulfur dioxide levels, the addition of ascorbic acid, and temperature control during winemaking can deter the colour-changing reaction.
If you’re concerned about pinking in your wine, talk to BRI’s Research Winery team.
To find out more, check out the following research: