Infusion and Decoction

Part of Pharmacy and Apothecary

The two foundational water-based extraction methods that form the backbone of herbal medicine — hot-steeping and simmering for different plant parts.

Why This Matters

Infusions and decoctions are the oldest and simplest forms of pharmaceutical preparation. They require nothing more than water, heat, and plant material. Yet executed properly, they are effective medicines that formed the pharmacological backbone of every medical tradition in human history before the twentieth century.

Understanding the difference between the two — and why it matters — separates effective herbal practice from ineffective ritual. A chamomile infusion made correctly extracts the calming flavonoids and bitter compounds from the flowers. The same chamomile boiled hard in a decoction destroys many of these compounds and degrades the preparation. Conversely, a willow bark infusion (hot tea) extracts some of the pain-relieving salicin, but a willow bark decoction extracts far more because the hard bark requires prolonged heat and moisture to release its contents.

In a community rebuilding pharmaceutical capability, these two techniques will be the daily workhorses — accessible to any literate practitioner with basic equipment. Mastering them means mastering the dosing, the timing, and the quality indicators that determine whether a preparation heals or merely tastes like medicine.

Infusion: Principles and Method

An infusion steeps plant material in water that has been boiled, but then removed from heat (or brought just to boiling and turned off). The hot water extracts water-soluble compounds from delicate tissue without the destruction caused by prolonged boiling.

When to use infusion:

• Flowers (chamomile, elderflower, lavender)
• Soft leaves (mint, lemon balm, plantain)
• Aerial parts (tops and leaves of thyme, sage, rosemary — though these can also be decocted)
• Any plant where heat-sensitive volatile compounds matter (smell and taste are good guides — if it smells strongly, use infusion)

Standard infusion procedure:

1. Bring fresh water to a full boil in a covered pot
2. For each 250 mL (one cup) of water, measure 2-5 grams of dried herb (or 4-10 grams fresh)
3. Remove from heat and add plant material, or pour boiling water over plant material in a separate vessel
4. Cover immediately and steep for 5-15 minutes. Covering is essential — volatile compounds escape with the steam
5. Strain through a fine cloth, squeezing the plant material gently to recover all liquid
6. Use immediately or store in a covered container for up to 24 hours in a cool location

Temperature matters: Water above 85°C is required for good extraction. Use freshly boiled water that has only cooled slightly. Water that has been sitting for an hour is too cool.

Dosing: Standard infusion doses range from 100-250 mL (small tea cup to large cup), taken 2-4 times per day. More concentrated infusions are used in smaller doses.

Strong medicinal infusion (higher dose preparation): Use 10-20 grams of herb per 250 mL water. Steep longer (20 minutes). Dose will be 50-100 mL, not 250 mL. Record the concentration in your dispensing log.

Decoction: Principles and Method

A decoction simmers plant material in water for an extended time. The continuous heat and moisture penetrate dense, hard material that would resist brief steeping.

When to use decoction:

• Roots (dandelion root, valerian, licorice, burdock)
• Bark (willow, cinnamon, oak)
• Seeds and berries (especially when hard-coated)
• Rhizomes (ginger, turmeric)
• Woody stems
• Any material that does not soften or release color quickly when steeped

Standard decoction procedure:

1. Coarsely chop or crack the plant material — cut roots into 1-2 cm pieces, crack seeds lightly
2. Combine plant material with cold water in a pot: 15-30 grams of dried material per 500 mL water as a starting point
3. Bring to a boil, then reduce to a gentle simmer
4. Simmer covered for 20-45 minutes. Most roots need at least 20 minutes; very hard bark may need 45 minutes
5. Check periodically. If liquid reduces below one-third of the original volume, add a small amount of hot water
6. Remove from heat and allow to steep an additional 10 minutes
7. Strain while warm — some preparations become very thick and hard to strain when cold
8. The finished decoction will typically be darker and more concentrated than an infusion of the same material

Yield and concentration: A decoction starting with 500 mL of water typically yields 350-400 mL of strained liquid. If you need a more concentrated preparation, continue simmering uncovered to reduce the volume further.

Combination Preparations

Some formulas contain both delicate aerial parts and hard roots or bark. Prepare them in two stages:

1. Decoct the hard material for 20-30 minutes
2. Remove from heat
3. Add the delicate material (flowers, leaves) to the hot decoction
4. Cover and steep 10 minutes
5. Strain

This preserves the volatile compounds of the delicate parts while fully extracting the roots and bark.

Concentration Techniques

Both infusions and decoctions can be concentrated for more convenient dosing or longer storage:

Syrup concentration: Add sufficient sugar (at least equal weight to liquid) to the strained preparation, heat gently until dissolved. Sugar acts as preservative — a properly made syrup can last weeks where a plain decoction lasts one day. See Syrups for full procedure.

Solid extract by reduction: Reduce a decoction to a thick paste by very slow simmering. The paste can be dried further, ground to powder, and formed into pills. One tablespoon of paste may represent a full dose. Label and store carefully — concentrate extracts are much stronger than fresh decoctions.

Quality Indicators

Learn to assess your preparations by appearance, smell, and taste:

Good infusion signs:

• Color appropriate to the herb (chamomile: pale yellow-gold; peppermint: pale green-yellow; elderflower: pale straw)
• Clear, not murky
• Strong characteristic aroma
• Flavor matches the herb — bitter, aromatic, sweet, or astringent as expected

Good decoction signs:

• Darker color than an infusion of the same material
• Some turbidity is normal
• Strong, concentrated flavor
• Astringent or bitter taste (depending on herb) is a good sign of tannin extraction

Warning signs in either preparation:

• No characteristic smell when it should have one
• Pale color from dark-colored herbs
• Fermentation bubbles after one day (discard and remake)
• Mold growth on the surface (discard entirely; clean vessel thoroughly before next use)

Practical Record-Keeping

Every batch should be recorded:

Date: [date]
Preparation: [infusion or decoction]
Herb: [name, dried/fresh, approximate age of dried material]
Quantity herb: [grams]
Quantity water: [mL]
Time/temperature: [steep time, boil time]
Yield: [mL of strained liquid]
Color/smell assessment: [description]
Dose dispensed: [amount per dose, frequency]
Patient/purpose: [identifier, condition]

This record allows you to reproduce successful preparations and troubleshoot failures. When a preparation unexpectedly fails to help a patient, the record tells you whether it was a dosing problem, a preparation problem, or a clinical problem.