A vinaigrette tastes too tangy due to excess acid (vinegar or citrus) or too oily due to an imbalance in the oil-to-acid ratio. Adjust by adding more oil to counter tanginess or more acid to counter oiliness, tasting as you go.
The key to a balanced vinaigrette lies in the ratio of oil to acid. A classic ratio is 3:1 (3 parts oil to 1 part acid), but this can be adjusted to your preference.
Too Tangy: If your vinaigrette is too tangy, it means there's too much acid. To fix this:
Add more oil, a tablespoon at a time, whisking well after each addition. Taste and repeat until the tanginess is reduced to your liking.
Consider adding a touch of sweetness, such as a small amount of honey, maple syrup, or agave. This can help balance the acidity.
If you've added too much acid initially, you can also dilute the vinaigrette with a little water, but be careful not to make it too thin.
Too Oily: If your vinaigrette tastes too oily, it means there's not enough acid to cut through the richness. To fix this:
Add more acid (vinegar or citrus juice), a teaspoon at a time, whisking well after each addition. Taste and repeat until the oiliness is balanced.
A pinch of salt can also help to balance the flavors and reduce the perception of oiliness.
Consider using a stronger flavored vinegar or citrus juice to provide more of a counterpoint to the oil.
Always taste your vinaigrette as you make it and adjust the ingredients to your personal preference. Different types of vinegar and oils have varying intensities, so the classic 3:1 ratio is just a starting point.