Decoction, infusion and maceration: which herbal preparation fits each plant?

All medicinal plant preparation methods explained: temperatures, durations, plant parts, mistakes to avoid, and a practical summary table.

You bought beautiful plants from a herbalist, but how do you prepare them to get the best out of them? The choice of method is not anecdotal: it determines the extraction of active compounds and therefore the effectiveness of your tea.

Why method matters

A plant's active compounds don't all release under the same conditions. Essential oils evaporate with prolonged heat, mucilages are destroyed above 60 °C, tannins require boiling, and some compounds are only soluble in alcohol.

The same plant can also behave differently depending on the part used. A flower tea, a root decoction and an alcohol extract are not interchangeable, even when the label carries the same common plant name.

Infusion: for tender parts

Pour simmering water (90-95 °C, never boiling) over leaves, flowers or flowering tops, and let infuse 5 to 10 minutes covered to preserve volatile compounds. Suitable for: chamomile, mint, lemon balm, verbena, linden, lavender, rosemary (leafy parts).

Common mistake: directly boiling water with the plant. This destroys some essential oils and produces a bitter taste.

Decoction: for hard parts

Reserved for roots, barks, seeds and woods, which only release their actives at high temperature for a long time. Place the plant in cold water, bring to a boil, then maintain a gentle simmer for 10 to 20 minutes. Filter, and consume warm. Suitable for: valerian, ginger, licorice, fresh turmeric, dandelion root, willow bark.

Cold maceration: to preserve fragile compounds

Soak the plant in room-temperature water for 6 to 12 hours (often overnight). This gentle method preserves mucilages, vitamins and heat-sensitive compounds. Suitable for: marshmallow (root and leaves), flax seeds, plantain, mallow.

Inhalation and fumigation

For respiratory issues, pour boiling water over aromatic plants (thyme, eucalyptus, lavender) and inhale vapors under a towel for 5 to 10 minutes.

Summary table

Preparation method by plant part

Plant material	Best method	Timing	Example plants
Thin leaves and flowers	Covered infusion	5-10 minutes at 90-95 °C	Chamomile, mint, lemon balm, linden
Thick leaves and flowering tops	Longer covered infusion	10-15 minutes near 95 °C	Thyme, rosemary, verbena
Roots, bark and hard seeds	Gentle decoction	10-20 minutes simmering	Valerian, ginger, licorice, dandelion root
Mucilage-rich plants	Cold maceration	6-12 hours at room temperature	Marshmallow, flax seed, plantain, mallow
Aromatic respiratory plants	Steam inhalation	5-10 minutes	Thyme, eucalyptus, lavender

Quality and hygiene basics

Preparation quality checklist

• Use drinking-quality water and clean utensils
• Measure with a kitchen scale when a recipe gives grams, because teaspoons vary widely
• Keep the cup covered during infusion to retain volatile compounds
• Discard any preparation that smells fermented, looks cloudy in an unusual way or was left warm for hours
• Do not reuse wet plant material across several days

Frequently asked questions

Can multiple plants be infused together?

Yes, provided their infusion times are compatible. Avoid mixing tender leaves (5 minutes) with roots (15 minutes): prepare them separately then mix.

Should I sweeten my tea?

Honey is preferable to sugar, and some honeys (thyme, lavender) potentiate tea action. Add when water has cooled below 40 °C to preserve enzymes.