There are a few different types of alcohol that can turn purple when exposed to certain conditions. The most common alcohols that exhibit a purple color change are red wines, certain clear spirits like vodka and gin, and pre-mixed cocktails. The purple color is usually an indicator that the alcohol has been oxidized or exposed to UV light.
Red Wine
Red wine is perhaps the most well-known type of alcohol that can turn purple when oxidized. Red wine gets its deep ruby color from anthocyanin pigments naturally present in the skins of red and black grapes. When exposed to oxygen, these anthocyanins can undergo chemical changes that shift the color toward a deeper purple hue.
Some examples of red wines that often turn purple as they age and oxidize include:
- Pinot Noir
- Cabernet Sauvignon
- Merlot
- Malbec
- Zinfandel
The purple color typically starts to develop along the edges of the wine in the bottle. As more oxidation occurs, the color change creeps inward. Over many months or years of careful aging, the entire wine may take on a purple tint.
Clear Spirits
Interestingly, clear spirits like vodka and gin can also turn purple when exposed to UV light. These spirits get their crystal clear appearance from the distillation process which removes color compounds. However, trace organic compounds may still be present.
When exposed to wavelengths of ultraviolet light, these trace compounds undergo a photochemical reaction that ultimately causes the spirit to take on a light purple tinge. This phenomenon is accelerated if the alcohol is stored in clear glass bottles that allow UV light to pass through.
Some of the organic molecules that have been identified as contributors to the purple color change include vanillin derived from the oak barrels, oleic acid, and quinoline-based compounds.
Pre-mixed Cocktails
Pre-mixed cocktails, especially citrus-based ones like margaritas, can also turn purple over time. Much like red wines, this is due to oxidation and interaction between certain ingredients.
For example, a pre-made margarita mix contains lime juice which is high in citric acid. The citric acid can react with plant pigments from the Triple Sec and dye compounds from any blue curaçao liqueur. Over time, these interactions produce a purple-ish color.
The same purple discoloration process applies to other citrus cocktail mixes like lemon, pineapple, and cranberry.
What Causes the Purple Color Change?
Now that we’ve covered some examples, what exactly causes alcohols to turn purple? There are two primary mechanisms at play:
Oxidation Reactions
– Exposure to oxygen causes structural changes to anthocyanin pigments in red wines, resulting in new pigments with purple hues
– In clear spirits, oxygen enables reactions between trace organic compounds that yield purple byproducts
– In cocktails, oxidation allows citric acid and other ingredients to interact and form purple dye molecules
Photochemical Reactions
– UV light exposure makes certain organic molecules found in clear spirits undergo rearrangements and changes that lead to development of purple color
– Photosensitizers like riboflavin can absorb light energy and transfer it to other compounds, facilitating purple color changes
Does a Purple Color Indicate Spoilage?
Many people wonder if they should be concerned when they notice their alcoholic beverages turning purple. Here are some key points:
– For aged red wines, a subtle purple hue along the edges is often indicative of proper aging and not a defect. However, a sudden distinct darkening likely means overoxidation and spoilage.
– With clear spirits like vodka and gin, a slight lavender tint from UV exposure does not necessarily mean the liquor is bad. Only dark purple colors typically signal contamination.
– For cocktails and mixed drinks, any distinct purple color change likely means the ingredients have overly oxidized or degraded and spoiled.
So in summary, a vivid dark purple color is bad news, while a light purple tinge may just be a normal part of aging for certain products. When in doubt, use your senses of smell and taste as well to determine if spoilage has occurred.
How to Prevent a Purple Color Change
If you want to enjoy your alcoholic beverages without any purple discoloration, here are some tips:
For Red Wines:
– Store the bottle on its side to minimize oxygen exposure to the wine surface
– Use corks or screwcaps to ensure a tight seal that prevents excessive oxidation
– Drink young red wines soon after opening instead of letting them sit
– Invest in a wine preservation system that replaces oxygen with inert gases
For Clear Spirits:
– Transfer the liquor to amber/blue colored bottles that block UV light
– Keep vodka, gin, and other spirits out of direct sunlight
– Don’t store opened bottles for extended periods
– Consider using UV-protectant sleeves on clear spirit bottles
For Cocktails and Mixers:
– Only prepare cocktails like margaritas immediately before serving
– Replace citrus juices regularly if making large batches of mix
– Add a small amount of lemon juice to help stabilize the color
– Store freshly mixed cocktails in the refrigerator and consume soon after making
Can You Reverse a Purple Color Change?
Unfortunately, there is no good way to reverse a purple color change once it has occurred in alcoholic beverages. The chemical transformations that take place are permanent.
However, it may be possible to mask minor purple discoloration in certain drinks by adding color modifiers. For example, a tiny amount of red dye could potentially cancel out a light purple tint in a clear spirit. But the only solution for substantial purple discoloration is to discard the alcohol.
To avoid wasting alcohol, it’s best to take proactive steps to protect drinks from extensive oxidation and light exposure in the first place. Proper storage methods and consuming opened bottles quickly can help maximize enjoyment without a purple surprise.
Conclusion
In summary, red wines, clear spirits, and mixed cocktails represent the main alcohol types prone to developing a purple tinge. While it may be visually unappealing, a slight lavender color does not necessarily indicate the alcohol is spoiled. However, a distinct dark purple hue likely means overoxidation has occurred. To enjoy your drinks to the fullest, consume them soon after opening and take steps to limit light and air exposure during storage. With some care taken, you can prevent your favorite spirits from inexplicably turning purple.