Oils
Oils are simply made. Using fresh herbs requires a bit more care than using dried herbs. The advantages of using fresh herbs are numerous: volatile oils, aromatic compounds are usually more potent in the fresh plant. Also, the more a plant is processed the larger the number of opportunities for contamination, oxidation and degradation.
Use an oil to capture lipophilic compounds, fat loving, fat soluble chemicals. This is a timeless technique for drawing the essence of aromatic, flavorful herbs like Rosemary, thyme, oregano, mints.
Cold Infusion of Oil
I prefer a cold infusion of oil. St. John's Wort is an example of a flower I infuse in cold oil.
Fill a jar (clear or amber) with crushed and macerated fresh herbs of choice. I macerate the herbs with a mortar and pestle in a bit of the oil used for the infusion.
Next, fill a jar to about a half inch from the top with the macerated herbs.
Cover the herbs with oil, olive oil is a good choice, seal the jar.
Because you have macerated the herb you have also removed water from plant tissue into the oil, this can cause spoilage. To slow spoilage I keep my cold infused oils refrigerated and try to use them within three weeks or less.
Because the herbs were macerated, you may use the macerated oil immediately or let it infuse and strengthen in the refrigerator for a few days.
Adding 1200mg of Vitamin E (three 400mg capsules) to a quart or liter of oil will help stabilize it by inhibiting oxidation.
After about a week in the refrigerator you may remove the herbs from the oil, use a wine press or press and squeeze them in a jelly bag, panty hose, cheese cloth.
Hot Infusion of Oil
A hot infusion of oil hastens the extraction of chemistry. Mullein flowers are infused in hot oil. The resultant mullein flower extraction is used by a few herbalists to treat external earaches. Fresh garlic can be prepared the same way. These oils are typically used fresh, immediately after they have cooled.
First, cut and macerate the herb in oil. Then...
Place a quart full of oil macerated herb in the top container of a double boiler (Pyrex glass or enamel pot are best).
Cover the herbs with olive oil.
Place the pan over boiling water, cover and simmer for one hour for chopped flowers, 2 hours for leaves and stems, 3 hours for roots.
Let the oil decoction cool, then press the oil out of the herb with a wine press, or squeeze the extraction as best you can in a jelly bag, panty hose or cheese cloth.
Add some vitamin E (1200mg per quart) to the oil to slow oxidation.
Use immediately, or seal and keep in refrigerator for two weeks.
Dried herbs may be treated in the same way as discussed above. One good thing is that the dried herb does not contaminate the infusion with water, the bad thing is that because of the drying process some of the herbs vital chemistry has been lost.