This concentrated powder can then be used dry or re-diluted in a now more potent liquid form. Certain ingredients can be extracted from the whole herb. This is done when the specific ingredient is perceived to have a unique, and more specific effect on human beings. These extracts are made with a variety of solvents such as acetone, hexane or methyl alcohol. The ingredient can then be used by itself or reconstituted into the original whole herb giving it more of this active ingredient than it has in its whole form.
Some companies use vegetable glycerin , a non-alcoholic extract to prepare tinctures.
Alcohol is a superior solvent to glycerin and a much better preservant. Glycerin is a good substitute however when alcohol is found to be an irritant to a particular individual. If necessary, alcoholic tinctures may be diluted in water or juice or allowed to evaporate in a glass of warm water in order to reduce any irritating effects.