Alcohol is one of the main workhorses in herbalism, so I want to give it its own little spotlight.
Ethanol is a simple molecule: two carbons, six hydrogens, and one oxygen (C₂H₆O). One end of the molecule is more water‑loving (the –OH group) and the carbon tail is more oil‑loving, which is why ethanol can dissolve both water‑soluble compounds and many “non‑polar” or oily constituents like essential oils, resins, and many plant pigments. When herbalists say non‑polar here, we just mean things that usually do not mix well with water; like your aromatics, many flavonoids, bitters, and lipophilic actives that give tinctures their depth.
Chemically, glycerin is also an alcohol, but a very different one: ethanol has one –OH group, while glycerin (glycerol) has three, which makes it thicker, sweeter, and more water‑loving and changes what it can pull from plants. Both can be beautiful solvents, but they behave differently with the plants and in the body.
Commercially, ethanol is made by fermenting sugars or starches (cane, grapes, corn, grains) with yeast and then distilling to concentrate the alcohol; spirits like vodka or brandy start as high‑proof ethanol and are diluted with water, with brandy then aged in oak so it can pull color and flavor compounds like vanillin and oak lactones from the barrel. But they all start off as ethanol.
In the alchemical lens, ethanol is often called the Mercury of the plant kingdom - the “universal spirit” that can be born from any fermentable plant and is essentially the same no matter which plant it came from. That universality is very different from essential oils, which are highly specific to each plant and definitely not interchangeable. (for example - you can definitely tell the difference between lavender essential oil and citrus oil; but if you fermented them and distilled their alcohol you would have a hard time differentiating them). It's no coincidence that alcohol is called a "spirit"; it points to that volatile, animating quality that can lift and carry the subtler aspects of a plant into a tincture or elixir.