Finely chop or grind your herbs with a mortar and pestle, and place them in your jar. (Sometimes I’m lazy and don’t do this, but I definitely notice a difference in the strength of my extract when I do.)
Once you have filled your jar with the right ratio of herbs, you’ll want to fill it the rest of the way with alcohol so that it completely covers the plants. To keep your herbs from molding, you need to make sure there’s about an inch of space above your herbs (that’s filled with alcohol) and that your herbs stay submerged.
Screw on the lid. If using a jar with a metal lid, you’ll need to keep it from rusting by placing a piece of parchment or plastic wrap over the mouth of the jar, prior to screwing on the lid. Place your jar in a cool, dry, dark cabinet.
Let the mixture steep for 8 weeks, shaking every other day. If the herbs are no longer totally submerged, top it off with additional alcohol.
At the end of 8 weeks, strain out the herbs and pour the tincture into a dropper bottle. To extract more of the tincture, wrap the herbs in cheesecloth and squeeze the remaining liquid from the herbs.