Herbal Preparations

  This is a short example of various preparation methods and various practices commonly used in herbalism.



  It is by no means comprehensive, and is literally just the short list. Despite this, we have provided this short reference to give an example of traditional use.

Infusion

  'Infusion' is essentially another word for 'tea.' While herbs could be steeped to infuse any substance, the implied solvent is water.

Decoction

  A decoction is an aqueous infusion of a single herb which has been allowed to simmer to a fraction of its former volume.

Hydrosol

  A hydrosol is a distillation of the decoction of an herb.

  It is usually a distillation entire, but may be fractionated by boiling temperature to get different hydrosol of an herb. Such a narrowly temperature-differentiated hydrosol can further be refined with help from a fractionating column.

Infused Oil

  When you choose a neutral carrier oil, such as olive or sunflower oil, and soak herbs in it, it becomes an infused oil.

Acetum

  An acetum is a white distilled vinegar infused with an herb.

Essential Oil

  The essential oils, in chemistry, refer solely to the allylbenzene constituents. In general herbal practice, the oil produced by steam distillation, such that a clean steam is passed through a column packed with the herb prior to condensation, is the substance generally referred to as the essential oil.

Tincture

  A tincture is an infusion of an herb into dry ethanol. An aqueous tincture is an infusion of an herb into a 50%/50% mixture of dry ethanol and water.

Balsam

  A balsam (or "balm") is a mixture of wax, such as beeswax or soy wax, with a small amount of a gentle food-grade oil such as soy or safflower oils to give it spreadable pliability. Almost any herbal preparation may be added.

Acid/Base Extraction

  An organic alkali may be made more soluble in water and less soluble in oil by the addition of an acid, such as vinegar. It may be made less soluble in water and less soluble in oil by the addition of an alkali, such as baking soda, ammonia, or woodlye.

  An organic acid may be made less soluble in water and less soluble in oil by the addition of an acid, such as vinegar. It may be made less soluble in water and more soluble in oil by the addition of an alkali, such as baking soda, ammonia, or woodlye.

  Note that most vegetable oils are themselves somewhat acidic.

Chromatography

  Chromatography relies on the different affinity of substances to a solvent, such as water or ethanol, and an absorbent.

  Put simply, if you take a strip of paper with a drop of ink, and drop ethanol on it slowly, that ink will spread.

  It is used analytically, in just such a form. Sometimes various developing agents are used - 9 parts sulfuric acid to one part formaldehyde, an example of the marquis reagent, produces a variety of colors with an astounding array of compounds, though it is not the only chemical test. Column chromatography is used instead to increase purification. It is what it says; paper fiber or silica gel or other absorbent in a column. Note that paper fibers can have their cellulose recrystallized from hot ethanol for a purer sorbent, yielding a single affinity per compound.

Recrystallization

  Because of the molecularly repeating nature of crystal formation, any single, well-formed crystal is likely to be of increased purity.

  This can be used to increase the purity of a compound. If, for instance, one can get crystals to form from a narrow fraction of distillation, say 1-2 degrees of temperature window, those crystals are purer than the distillate itself. If itself re-recrystallized from a well-distilled, high-purity suitable solvent, free from the broth, any single, well-formed crystal would be considered a fairly pure example.

  Evaporative recrystallization is just letting the solvent evaporate. The slower the evaporation, the larger the crystals!

  Most other forms of recrystallization are thermal recrystallization. Single-solvent recrystallization involves boiling a substance in the solvent, adding more until no more can dissolve, filtering, and letting it cool - again, the slower it cools, the bigger the crystals, and the easier it is to get a single, high-quality crystal to recrystallize again.

  Dual-solvent thermal recrystallization involves finding solvents that will mix (are miscible), and, well, using that as your recrystallization solvent. Miscible fractionation involves adding a miscible solvent dropwise until the first crystals or oil crashes out of solution, and this can be a starting broth for thermal dual-solvent recrystallization.

  Dual-solvent evaporative recrystallization is also possible; if a mix of acetone and water is kept in a jar, a cloth stuffed with salt and a lid will dry out the water slowly until the solvent is pure acetone.




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