The term essence implies a preparation of the essentially active portion of a substance, but it is widely and erroneously applied to a variety of decoctions, infusions, solutions, tinctures, and fluid extracts, as well as the alcoholic solutions of essential oils from plants. In preparing essences, the solid ingredients must be thoroughly bruised, powdered, or sliced, so as to expose them completely to the action of the spirit. When the active principle to be obtained is partly fixed and partly volatile, the most suitable process is simple digestion in alcohol, either weak or absolute, according to the solubility of the substance. The digestion or maceration should be continued for at least 10-14 days, and the materials should be repeatedly agitated, so as to ensure contact between all fragments. A more concentrated solution may be obtained by the process of displacement or percolation. When the object is to extract only an aromatic and volatile principle, a better method is to digest the materials in alcohol for a few days, and then subject the whole to distillation: the alcohol passes over in vapour, carrying with it the bulk: of the volatile matters vaporizable at or below the distillation temperature of the alcohol employed.
For all first-class articles, the alcohol used must be pure, and free from colour, odour, and flavour. The following are amongst the most important essences in use.
Aconite - 8 oz. dried powdered aconite herb, 16 oz. rectified spirit; macerate 4 days at 68° F. (20° C), press, strain; the marc or residue is again macerated with a little spirit and pressed as before, so that the weight of the united tinctures may be double that of the herb.
1 fl. oz. essential oil of allspice (pimento), 1 pint strongest rectified spirit; agitate till perfectly mixed; next day decant the clear from the sediment.
(I) 1 fl. oz. essential oil of almonds, 1 pint spirit; proceed as Allspice.
(2) 1 fl. oz. essential oil, 7 fl. oz. spirit.
(1) 1 lb. ammo-niacum in tears, bruised in a cold mortar with 1/2 lb. coarse, well-washed, silicious sand or powdered glass, and 1./2 pint rectified spirit gradually added; trituration is continued till the whole is reduced to smooth paste, and it is then placed in a wide-mouthed bottle with 1/2 pint spirit of wine; digest for a week with frequent stirring, and after allowing to settle, decant the clear into another bottle for use.
(2) Reduce 1 lb. ammoniacum to a cream with £ pint boiling water; as soon as cool, put into a strong bottle, and cautiously add 1 1/4 pint rectified spirit of wine; cork tightly, and let macerate for a few days; put the bottle in a warm place for the sediment to go down, and filter off through flannel.
(1) 1 lb. anchovies, boned, pulped in a stone mortar, and passed through a hair or wire sieve; boil the bones and the portion that will not go through the sieve in 1 pint water for 15 minutes, and strain; to the strained liquor add 2 1/2 oz. each of salt and flour, as well as the pulp, and simmer the whole for 3 or 4 minutes; remove from the fire, cool, and mix in 1/2 pint strong pickling vinegar; bottle, and secure with wax, capsule, or bladder.
(2) 7 lb. anchovies, 9 pints water, 1 lb. flour, 1 lb. salt.
1 oz. bruised angelica root, 8 oz. rectified spirit, 16 oz. water; digest, and distil over 6 oz.
1 oz. oil of anise, 8 oz. rectified spirit.
(2) 5 dr. recent extract of henbane, 2 fl. oz. rectified spirit; digest a week. Antihysteric. - 3 gr. potassium cyanide, 1 dr. powdered sugar, 4 fl. dr. rectified spirit, 4 fl. dr. orange-water; shake together till dissolved.
1 dr. hay saffron, 6 fl. dr. rectified spirit; digest together, filter; to filtrate add 1 dr. oil of cinnamon, 1 dr. powdered white sugar, 2 fl. dr. rectified ether, 1/2 dr. oil of nutmeg, 1/2 dr. essence of ginger; after shaking and a few days' repose, decant the clear.
(1) 4 dr. resinous extract of yellow bark, 1 1/2 fl. oz. rectified spirit, 1/2 fl. oz. tincture of orange-peel, 1 fl. dr. acetic acid; digest a week.
(2) 1/2 dr. quinine disulphate, 2 dr. resinous extract of bark, 2 fl. oz. rectified spirit; digest a week.
(1) 1 lb. lean beef chopped small, 1/2 pint water; put into large bottle and shake violently 1/2 hour; strain the liquid into a jug; boil the solid residue in 1 pint water for 20 minutes; strain, and add the liquid to the previous cold infusion; evaporate to consistence of thin syrup, add salt and spice to taste, and while boiling hot pour into cans or (previously heated) bottles, hermetically seal, and store in a cold place.
(2) Boil the sliced beef and water in a bottle suspended in water in a pot for 1 or 2 hours; decant the liquid, skim, and flavour.
4 oz. wormwood, 1 oz. gentian root, 1 oz. bitter orange-peel, 1 oz. blessed thistle, 45 oz. rectified spirit; digest a week.
(1) 4 1/2 oz. clean camphor dissolved in 1 gal. rectified spirit.
(2) 1 oz. camphor, 10 oz. rectified spirit.
(3) 13 fl. dr. tincture of camphor, 1/2 fl. dr. tincture of myrrh, 18 1/2 fl. dr. rectified spirit.
(4) 1 fl. oz. spirit of camphor, 7 fl. oz. proof spirit.
(5) 1 dr. camphor dissolved in 2 1/2 oz rectified spirit; add 1/2 oz. water.
(6) 1 dr. powdered camphor dissolved in 12 fl. oz. water saturated with carbonic acid gas.
5 1/2 lb. lesser cardamom seeds ground in a pepper-mill, 1 gal. rectified spirit of wine; digest for a fortnight, press, filter.