As an expert sommelier and brewer, I can confidently say that red wine vinegar does not go bad after opening. In fact, it is perfectly safe to use even if it has been sitting in your pantry for a while. This is because red wine vinegar is highly acidic, which creates an inhospitable environment for harmful bacteria to survive.
However, it is important to note that the quality of red wine vinegar may deteriorate over time, especially if it has been opened frequently. The vinegar may become darker in color, and you may notice the formation of solids or cloudiness in the bottle. While these changes do not indicate spoilage or safety concerns, they can affect the taste and appearance of the vinegar.
If you prefer a clear and pristine red wine vinegar, you can strain off any solids or cloudiness that may have formed. Simply pour the vinegar through a fine-mesh strainer or cheesecloth into a clean container. This will remove any unwanted particles and give you a smoother consistency.
It is worth mentioning that the shelf life of red wine vinegar, whether opened or unopened, can vary depending on how it is stored. To maximize its longevity, it is best to store red wine vinegar in a cool, dark place, away from direct sunlight and heat sources. This will help maintain its quality and flavor for a longer period.
In my personal experience, I have used red wine vinegar that had been opened for several months without any issues. The vinegar tasted slightly stronger and had a deeper color, but it still worked well in salad dressings, marinades, and other culinary applications. However, it is always a good idea to use your senses and trust your judgment when determining the quality of any food product, including vinegar.
To summarize, red wine vinegar does not go bad after opening. While it may undergo changes in color and consistency over time, it is still safe to use. If you prefer a clearer vinegar, you can strain off any solids or cloudiness that may have formed. Proper storage in a cool, dark place will help maintain the quality of red wine vinegar for a longer period.