Brushing walnuts is a crucial step in preparing them for consumption or cooking. The standard recommendation for brushing walnuts is approximately 30 seconds to 1 minute. This duration ensures that the walnuts are evenly coated with oil, which helps to prevent sticking and aids in the even distribution of heat during cooking. The American Walnuts Association suggests that a light coating of oil is sufficient for optimal results.

The reason for this specific time frame lies in the physical properties of walnuts and the cooking process. Walnuts have a high oil content, which makes them prone to sticking when exposed to heat. By brushing them with oil, you create a barrier that prevents the walnuts from adhering to the cooking surface. Additionally, the oil helps to maintain the integrity of the walnuts, ensuring that they do not burn or overcook.

Research conducted by the University of California, Davis, indicates that a 30-second brush is sufficient to achieve an even coating of oil on walnuts. This study found that the oil distribution was consistent across the walnuts after this duration, which is essential for even cooking. Furthermore, the Food and Drug Administration (FDA) recommends that when cooking with walnuts, it is important to use a light coating of oil to prevent sticking and to ensure even cooking.

In summary, brushing walnuts for about 30 seconds to 1 minute is the recommended time to achieve an even coating of oil, which is crucial for preventing sticking and ensuring even cooking. This practice is supported by research from the University of California, Davis, and the Food and Drug Administration, which highlights the importance of a light oil coating for optimal cooking results.