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Open Source Apothecary At Home / Preparations
The commonest preparation in the world, and the one most often made in a way that loses most of the active.
methodAn infusion is a water extraction of the polar fraction of a plant. Water does not dissolve everything, so the first question is whether the thing you want is water-soluble at all. Tannins, flavonoids, mucilage, sugars, most organic acids, and many alkaloid salts are; waxes, fixed oils, resins, and the bulk of the essential-oil monoterpenes are not.
The method, and why each step is there:
1. Use dried leaf or flower, 1-2 g (about 1-2 teaspoons) per 250 mL of water. Fresh material carries water that dilutes the extraction and can turn rancid; a weighed amount is the only way to make two batches comparable. 2. Cut or crumble, do not powder. Cutting increases surface area without releasing fine particles that cloud the infusion and pass through most strainers. 3. Pour water just off the boil — about 95-98 C — and cover the vessel immediately. The cover is not a habit. The compounds you can smell are by definition volatile, and an uncovered cup loses them to the room; the same molecules are the ones doing aromatic work in digestive and respiratory tea. 4. Steep 5-10 minutes for leaf and flower, 10-15 for root, bark and seed. Extraction of polyphenols rises steeply with both temperature and time and then flattens; prolonged boiling past that flattens further but starts to degrade heat-labile compounds, and it also concentrates the bitter and astringent fractions. 5. Strain and drink it the same day. An infusion is a nutrient broth as well as a medicine. Left at room temperature it grows bacteria within hours.
Cold infusion is a different preparation with a different output. Steeping the same herb in cold water for 6-12 hours extracts less of the tannins and bitter compounds and much more of the mucilage, because mucilage is a polysaccharide that heat degrades. For a demulcent effect on a sore throat or an irritated gut, cold infusion is the correct method and a hot tea is the wrong one.
What to expect from the numbers. Where trials on this site used a tea, they usually specified a dose and a steep time, and those figures are the ones on the relevant remedy page. A "cup of tea" is not a dose until it is a weight, a volume and a time.
Hence, LVI is a source of bifunctional antioxidants, and thus in vivo studies of the antioxidant capacity of LVI would be useful to evaluate its potential as an ingredient in antioxidant drinks.PubMed 21434775 ↗
The overall results of this study demonstrate that fresh Brassica vegetables retain phytochemicals and TAC better than frozen samples.PubMed 20218674 ↗
All the domestic processing and cooking methods could reduce the contents of phytic acid and polyphenols but germination for 48 hours seemed to have a marked lowering effect on the levels of these antinutrients in peas.PubMed 7971780 ↗
Overall, our review provides valuable information for devising effective strategies to produce high-quality MAPs products.PubMed 38781639 ↗
Infusion — leaf, flower, soft aerial parts
Cold infusion — mucilage and delicate aromatics
Decoction — root, bark, seed, hard woody material
Cover the vessel. This is the single step most often skipped and the one that wastes the most material. Volatile monoterpenes are the therapeutic fraction in peppermint, chamomile, fennel and thyme tea, and they leave an open cup.
Taste is a crude assay. A properly made infusion of chamomile is faintly sweet and aromatic with a bitter edge; if it is tasteless, the material was old — volatile content falls steeply in the first year of storage.