Solar Infusion Method
When I’m not in a hurry I like to use the solar infusion method. This method takes more time but reduces chances for mistakes, plus your infused oil will have the extra blessing of the sun. Place your dried herbs in a clean, dry jar. Moisture in the jar can introduce bacteria to the infusion and cause the oil to go rancid.
Fill the jar loosely, about two-thirds full. Pour your fixed oil over the herbs, making sure none of the herbs break the surface of the oil. Stir lightly with a wooden spoon to release any possible air pockets. Put the jar in a brown paper bag and place the package in a spot where it will get lots of sun during most of the day.
Heat can make oil go rancid, but as long as the herbs are in the oil, this is not a problem. Leave the herbs in the jar for at least two weeks. The oil may expand and spill out of the top of the jar, but don’t worry about it. Every day, shake the jar. When the oil has taken on the properties of the herbs and the plant material looks spent (after about two to three weeks), it’s time to strain the herbs. Make sure that you press as much of the oil out of the remaining herbs as you can. Store the infused oil in a glass bottle in a cool, dark place.
Double Boiler Infusion Method
If you need the oil in a hurry, you can use several quicker methods for infusing the oil, including using a double boiler. As in the solar method, place the herbs in the pan and cover with oil. Use about one part herb to two parts oil.
Heat the oil over simmering water, being especially careful not to get the oil too hot. If you have a cooking thermometer, track the temperature to keep the oil around 120 degrees. You want to warm the herbs, but not let them simmer. If you see any bubbles appear around the edge, turn the heat down. Stir occasionally. Remember, you aren’t trying to cook the herbs. If they become
crisp or crunchy, you have overheated the oil and should compost the oil and herbs and start over. Stay with the oil until it’s finished. Heat the herb and oil mixture for at least 45 minutes.
Oven Infusion Method
You can also infuse oil in the oven if your oven has a low enough setting. Place the herb and oil mixture in a covered dish in the oven and heat at the lowest temperature, usually about 150 degrees. Leave the dish in the oven for about 2 hours, stirring occasionally. Again, keep an eye on the process to keep from ruining your oil.
Adapted with permission from Earth Mother Herbal (Fair Winds, 2002) by Shatoiya de la Tour.