Caution: Before making anything that may be used topically or ingested, know about ALL of the properties of the ingredients you will be using and HOW they interact will each other.
That being said, on with the post.
Essential oil: Are oils that are derived from any botanical source, that is said to contain the "Essence" of said plant
Extracting an essential oil, can be a daunting task.
There are 3 methods (That I know of) to extract essentials
1. compression: taking the botanical in question an pressing it until you extract the oils you desire. (Works best on high yield botanical. such as fruit skins. Especially citrus fruits)
2. submerged distillation: Placing the plant material directly in a solution of water, and boiling that water into a condenser/separator
(You can build a distiller like this reasonably affordably with a large chili style pot, a large metal salad bowl, a brick with a flat top and bottom, a collection dish [that will not melt under moderate heat] and ice)
3. Steam distillation: similar to the previous except that the botanical are placed in a tray that sits above the water line and the steam passes through them.
Hydrosols: is a term for water that has some plant essence in it. When essential oils are extracted through distillation the water that is separated off, is a hydrosol. Some of the most popular hydrosols are rose-water and sage-water.
Infusions: A carrier oil that is infused with the essence of your botanicals.
1. choose your carrier oil. Any that don't have a strong scent or flavor of their own will do. I like vegetable oil or grapeseed oil.
2. boil you oil in a pot (Oil only: the temp that oil boils at would likely damage your botanicals essentials)
3. place your botanicals into a jar(one that can handle HOT temps) and fill it halfway with your botanicals
4. turn off your oil and allow to cool until it stops bubbling. Pour oil into jar until just below the hip.
5. Allow jar to cool to room temp before sealing
6. wait at least one week for essences to acclimate into the carrier. For added potency I like to leave the jar where it can collect moonlight (I also like to leave it from one full moon to the next)
Tinctures: same concept as an infusion except rather than using a heated oil, you use an odorless, and tasteless alcohol to capture the essentials. (Most commonly used is Vodka)
You need to use a high proof alcohol (80 or better) and use colored glass jars (Brown is preferred) as tinctures are photoreceptive and excess light may effect the quality of your product.