Fresh Rosemary
Rosemary oil begins with the best fresh rosemary that you can find. Dried is really not comparable when making an oil. You always want to use organic, fresh rosemary. To create 8 oz. of infused rosemary oil, you want about 1 cup of fresh rosemary.
Base Oil
The base oil, of course, affects the overall quality of the rosemary oil, so it is important to get a good quality, food grade oil, such as grape seed, sweet almond or jojoba. A light, extra virgin olive oil will also work to make rosemary oil.
Heat Infusion Method
The heat method will produce a stronger flavored oil. The fresh rosemary should be rinsed and patted dry, then put into a heatproof glass bowl with the oil. The glass bowl should be set over a pot of water, kept on a low simmer, for two to three hours. Once the oil has infused for two to three hours, it should be strained through cheesecloth and placed into a sterilized jar.
Cold
The cold method is simpler but takes longer and the oil may not be as strong. To create a cold infusion, simply place the rosemary in a sterilized jar or bottle. Pour the oil over the rosemary, seal tightly, and let sit in a sunny windowsill for three weeks or so, shaking once a day. Strain the finished product and store in a sterilized jar or bottle with a tight seal.
Tags: fresh rosemary, glass bowl, Infusion Method, sterilized bottle, three hours