Vinegar is a common ingredient in many types of cooking. Some types of vinegar can also be used as a salad dressing. It is a common ingredient in Easter egg dyes where it is mixed with food colouring. The food colouring gives the vinegar its hue and the vinegar affects the colouring in other ways.
Vinegar Changes Color
The primary effect that adding food colouring to vinegar offers is that the vinegar changes colour. This is due to the colouring agents of the food colouring. It is the same as if the colouring was added to any liquid or food. That colour is diluted and spread throughout the liquid giving its colour to the entire solution. Add red food colouring and your vinegar will turn red. Add green to turn it green and so on. The more food colouring you add, the more concentrated the colouring content and the brighter the colours.
Vinegar is used in making some kinds of dyes. This is most commonly done when colouring eggs for Easter. Vinegar is slightly acidic. It is in-between tomato juice and lemon juice on the pH scale with a pH of around 2.4. This allows the vinegar to react with the food colouring by breaking it down. This helps the dye maintain its colour once applied to a surface such as eggshell. It also makes the dye stick better to the egg than if the colouring was used with plain water.
Effect on Vinegar
The food colouring is affected more than the vinegar. Vinegar that has had colouring added to it can still be used in normal ways such as on salads, in cooking or other uses. The vinegar will be a different colour, but the chemical make-up of the colouring is mild. The changing of colours is its only affective property. The taste of the vinegar will remain unchanged as well as the smell. Of course, this is assuming that only a few drops of colouring have been used. It only takes a drop or two to colour a liquid amount several times larger. If enough colouring has been used to dilute the vinegar, it can no longer be used normally.
Food colouring can be added to any type of vinegar that you may be using. If using vinegar on food, you can add food colouring to spice up the dish with a variety of colours. Salad dressing can be made brighter and more vibrant with a few drops of food colouring. Some people won't care for unnaturally coloured foods though, so be careful with which foods you add coloured vinegar to. You can also use red food colouring to give colour to the classic vinegar volcano science project. When the acidic vinegar breaks down baking soda and begins to fizz, some red food colouring can make it look more like lava.