Herbal Decoction Ratio Calculator
Calculate water-to-herb ratio and simmer time for herbal decoctions.
Standard 1:8 ratio for roots, barks, and tough plant material with traditional methods.
Decoction is for the tough stuff: roots, barks, and woody plant material. Anything you cannot reasonably steep with hot water alone needs simmering to break down cell walls and extract constituents. Astragalus, dandelion root, burdock, ginger root, willow bark, marshmallow root: these are decoction territory. Leaves and flowers are usually infusions, not decoctions.
The standard ratio is 1:8 by weight, dried herb to water. That means 28 g of dried root takes 224 ml of water to start, near enough a cup. Note how much heavier that is than an infusion, which runs nearer 1:33 even at nourishing strength. Roots hold on to their constituents, so they need both the heat and the concentration.
After simmering you lose 30 to 50% of the water to steam, so a 224 ml start yields somewhere around 130 ml. Working backwards, a full 240 ml cup of finished decoction means starting with about 1.7 cups of water and 50 g of root.
Simmer time depends on the material.
- Soft roots (dandelion, burdock): 15-20 minutes
- Medium-firm roots (ginger, turmeric): 20-30 minutes
- Tough roots (astragalus, codonopsis): 30-45 minutes
- Hard barks (willow, slippery elm): 20-30 minutes
- Woody material (cinnamon sticks, oak bark): 30-60 minutes
Always cover the pot during simmer. Volatile compounds (including the ones doing real work) evaporate fast in an uncovered pan.
Cold-start matters. Add the herb to cold water, then bring to a low simmer. Throwing dried root into already-boiling water shocks the cells and seals some constituents inside. The cold-start gives time for water to penetrate the material before heat fully kicks in.
Strength variations.
- Standard: 1:8 ratio, 20-30 min simmer
- Strong (medicinal dose): 1:4 ratio, 30-45 min simmer
- Concentrated (decoction syrup base): 1:2 ratio, simmered to half, then reduced further
Storage. A finished decoction in the fridge keeps 48-72 hours. Add a teaspoon of brandy per cup for a week of life. For longer storage, decant into a sterilized bottle while still hot, which gives a couple of weeks. For months of shelf life, turn the decoction into a syrup with honey or sugar.
Worked example. 30 g of astragalus root.
- Water at 1:8 = 240 ml
- Simmer 30 minutes covered
- Strain, expect around 144 ml of finished decoction
- That is four doses of 30 ml, a typical immune-tonic amount, with a little left in the pot
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