Some cooks choose to rinse their onions after chopping them to reduce their sharpness, strong flavor, or pungency. This practice is particularly common when working with raw onions, as raw onions can sometimes be too intense or overpowering in certain dishes, such as salads or salsas.
When you chop an onion, you release certain compounds, including sulfur-containing compounds, which contribute to its strong flavor and characteristic pungency. Rinsing chopped onions under cold water can help wash away some of these compounds from the surface, resulting in a milder and less intense flavor.
The effectiveness of rinsing depends on the onion variety and its freshness. Some onions are naturally milder than others, and the older an onion is, the stronger its flavor tends to be. In some cases, rinsing may have a significant impact, while in others, it may only slightly reduce the intensity of the onion's flavor.
It's worth noting that rinsing chopped onions may not be suitable for all recipes, especially those that rely on the onion's strong flavor to enhance the overall dish. In such cases, you can skip the rinsing step or adjust the amount of onion used to achieve the desired taste.
Ultimately, whether to rinse onions after chopping them is a matter of personal preference and the specific requirements of the dish being prepared. Some cooks prefer the milder taste of rinsed onions, while others embrace the full flavor and aroma of freshly chopped onions.