Doubling herbs, spices, and salt can easily overwhelm a dish. Starting with 1.5 times the amount allows for better control over the final flavor profile and prevents over-seasoning.
When you double a recipe, the surface area of the ingredients doesn't necessarily double proportionally. This means the concentration of flavors from herbs, spices, and salt can become more intense. For example, if you double the amount of chili powder, the heat might become disproportionately strong because the other ingredients haven't increased in the same way to balance it out.
Starting with 1.5 times the original amount of these ingredients provides a buffer. It allows you to taste the dish as it cooks and make adjustments based on your preference. You can always add more to reach the desired flavor, but it's much harder to remove excess seasoning. This approach ensures a more balanced and palatable final product. It also accounts for variations in ingredient potency; for instance, one batch of dried oregano might be stronger than another.
Always add dried herbs and spices earlier in the cooking process to allow their flavors to fully develop. Fresh herbs are best added towards the end to retain their bright, vibrant taste.