Glycerites, vinegar extracts and oxymels

Three alcohol-free options, each with a different solvent and therefore a different set of compounds it can carry.

Glycerites. Glycerol is a viscous, sweet, mid-polar solvent. It dissolves tannins, sugars, some glycosides, and a fair range of mid-polar compounds, and it does not dissolve resins or fixed oils well. It extracts more slowly than ethanol and it needs water present — a pure glycerol extraction of dried material is poor because the plant cells need water to swell and release their contents, so the working ratio is roughly glycerol 60-80% with the balance water.

Glycerites are sweet enough that children accept them, which is their main practical advantage and also a risk: they are not safer pharmacologically, only more palatable, and a palatable preparation in an unlatched cupboard is a paediatric ingestion waiting to happen. Shelf life is 1-3 years, shorter than an ethanol tincture, because glycerol is not as inhibitory to microbes at working strength.

Vinegar extracts (aceta). Acetic acid at 5% is a weak acid and a modest solvent. Its genuine strength is that it converts alkaloids into their acetate salts, which are water-soluble, so vinegar is the traditional menstruum for alkaloid-containing plants — and its genuine weakness is that it extracts resins and oils poorly. An acetic extract tastes of vinegar and is usually taken in larger volumes than a tincture.

Vinegar preserves reasonably well by acidity alone, but not against all spoilage organisms; a vinegar extract is not shelf-stable indefinitely and should be kept cool. Vinegar also attacks metal lids, so use a plastic-lined or glass closure.

Oxymels. Honey and vinegar together. The honey raises the solids and lowers the water activity, which is a preservation mechanism distinct from the acid; the result is self-stable and pleasant. The traditional ratio is roughly 1 part vinegar to 2-4 parts honey by volume, which puts it in the range where the honey's water activity is doing real work. An oxymel is a good vehicle for aromatic and demulcent herbs and a poor one for anything needing a concentrated dose, because the sugar limits how much vinegar you can include.

What none of the three can do. None carries a non-polar compound usefully. If the active is a resin, a fixed oil, or a highly non-polar terpene, the alcohol-free options are the wrong method and the honest answer is a tincture or an oil preparation.