How does salad burn your lips when vinegar is added?

Salad doesn't actually "burn" your lips when vinegar is added. The sensation you're describing is likely due to the acidity of the vinegar, not burning.

Here's why:

* Vinegar is acidic: Vinegar is a weak acid, and its acidity can irritate sensitive skin, especially around the mouth.

* Sensitivity varies: Some people are more sensitive to acidity than others. If you have sensitive lips or skin, you may be more likely to feel a tingling or burning sensation.

* Concentration matters: The concentration of vinegar in the salad dressing can also play a role. A higher concentration will likely be more irritating.

* Other factors: The temperature of the salad, the amount of vinegar used, and the ingredients in the salad can also influence the intensity of the sensation.

It's important to note that:

* Vinegar is generally safe to consume: The acidity of vinegar is usually not a cause for concern, and it's a common ingredient in many foods.

* If you experience significant discomfort: If you find that vinegar causes you a lot of discomfort, you may want to try using less vinegar or choosing a different type of dressing.

Overall, the sensation of "burning" lips from vinegar in salad is likely due to the acidity irritating your lips. If you are concerned about your sensitivity, consult with a doctor or a dermatologist.