Short answer: YesLong answer: Yes, grinding will increase the surface area of your herb therefore increasing the rate of reaction, essentially making it easier to heat up. The same reason why its easier/faster to mix a teaspoon of sugar into a tea, then it is to mix a cube of sugar (An anology which may help you understand the ‘why’). However, ensure you do not compact the dry herbs as this allow for less room for air to pass through and will cause tighter airflow.