Use a glass jar with a well-fitting lid and pack it somewhat loosely with fresh herbs of choice (more loosely than when making a tincture). Make sure the jar is absolutely dry; moisture can ruin the batch. Pour cold pressed olive oil or other carrier oil of choice over the herbs and let it filter down through the herbs. Keep pouring in oil until the herbs are completely covered by it. Make sure the herbs are submerged in the oil so that no plant matter is exposed to the air. (Marbles and rocks can be used to weigh them down.) Cap and label the jar with the date and contents. Place a bowl under your oil jar as it steeps, since a little oil usually seeps out from beneath the lid, running down the side of the jar and creating an oily mess. By keeping the lids off the jars you can avoid some of the mess, and this also provides an aerobic environment that can help to prevent the growth of mold. I often place herb-and-oil-filled jars on a jelly roll pan in the oven with the pilot light on, as the warmth helps to encourage the extraction process. After steeping, strain the oil by placing a strainer lined with a thin cloth over a bowl and pouring the entire contents of the jar into the cloth-lined strainer. ow the oil to seep into the bowl, then gather the ends of the cloth together and squeeze out any remaining oil. ow the strained oil to sit for a couple of days, which allows the water from the fresh herbs to collect at the bottom of the jar. Next pour or siphon off the oil and discard the liquid that has collected at the bottom. If you don’t separate out the water, the oil may spoil. Store oils in a cool, dark, dry place. v
Herbal-Infused Oils with Heat. This method is excellent for fresh herbs that contain a lot of moisture or protein. It can also be used with dried herbs to speed the infusion process, and sometimes yields a more potent oil. Heat helps to evaporate water from the fresh herbs, which discourages the growth of mold and prevents the oil from rotting. The addition of heat also speeds up the infusion process, making the herbal-infused oil ready in about 10 days. Place your herb-and-oil-filled jar uncovered on a heat source that does not exceed 125 degrees. You may want to place the mixture in a wide pot so that more surface area is exposed to the air, promoting the evaporation of water. The heat source can be a radiator, warming tray, warmer shelf of a woodstove or whatever else in your home will offer this kind of consistent, gentle heat. You can also place the mixture into an electric cooking pot or turkey roaster, with the lid on but the vent open, set on low. With an electric cooking pot, the lowest setting is above 125 degrees, so you will need to turn it on and off throughout the day to adjust the temperature. Keep infusing the herb-and-oil-mixture for 10 days, then proceed to strain and separate the oil as described above. Note: If you don’t have a thermometer, use your skin as a guide and feel the oil to make sure it is not too hot. Oil at 125 degrees is still cool enough to touch without burning yourself, although if you continue to touch the oil for a few seconds it should feel a little too hot for comfort.