How Herbal Tea Is Prepared

There is no single method for all herbs. The right method depends on the plant part and the product, and the EU herbal medicines committee says that for herbal teas the preparation method can matter because different preparations may exert different actions and sometimes have a different safety profile. It also notes that tea concentration varies with growing, harvesting, drying and storage as well as with the preparation procedure. [1] Always follow the instructions on a product made for tea, and ask a pharmacist if you are unsure.

Infusion, decoction and maceration (EU definitions)

• Infusion: boiling water poured on the herb, whole or cut to a suitable size, left to steep for a defined time, usually 5 to 15 minutes when not otherwise specified. The EU notes that boiling water is important for lowering the microbial load of the herbal material. [1]
• Decoction: the herb is covered with cold water, heated to the boil and simmered for a defined time, usually 15 to 30 minutes when not otherwise specified. A decoction is generally not suitable for herbs with volatile active constituents. [1]
• Maceration: the herb is soaked in water, which the EU template describes as cold or lukewarm, for a defined time, covered and stirred. [1]
• Which method for which part: infusion is usually appropriate for leaves, flowers and delicate parts, whereas decoction or maceration is appropriate for roots, rhizomes and bark. [1] Marshmallow root, for example, is prepared as a macerate in EU monographs. [2]
• Aromatic herbs such as mint may be infused at the end of a decoction when a mixture needs different methods. [1]

Practical points from the EU template

• Keep the infusion covered with a lid while it steeps, and stir at regular intervals. For loose herbs, filter through a tea strainer and press the residue to obtain more liquid; for sachets, gently squeeze the sachet. [1]
• Let a hot infusion cool to a suitable temperature before drinking. [1]
• Drink an infusion or decoction shortly after preparing it. If not, store it covered in the refrigerator for a maximum of 24 hours. A macerate should be drunk immediately after preparation; if not, it should be discarded. [1]

Loose leaf vs tea bags

The EU template covers both: loose herbs are strained and pressed, sachets are squeezed. [1] We found no source we could read comparing the two for quality or effect, so we make no claim that either is better. The amount that matters is the amount of herb used, which a label should state.

Hot vs cold

Hot water (infusion, decoction) and cold or lukewarm water (maceration) extract different amounts of different compounds, so they are different preparations. [1]

Drink temperature

IARC classified drinking very hot beverages, above 65 °C, as probably carcinogenic to humans (Group 2A) for esophageal cancer, and said temperature rather than the drink appears responsible; the evidence was limited. [3] The EU template also says to let a hot infusion cool before drinking. [1]

Tea bags and plastic

A 2026 systematic review of 19 studies found tea bags that contain plastic (for example non-woven polypropylene or nylon) released large numbers of micro- and nanoplastic particles, often billions per bag, when brewed in hot water (typically at or above 95 °C); release varied with the bag material, temperature, time and agitation, and even paper-based or "eco-friendly" bags released measurable amounts. The review says human health risk assessments are lacking and exposure estimates are preliminary. [4] This is a reason to check what a bag is made of, not proof of harm.

Storage and contamination: what is and is not known

Proper evidence not found on how long dry herbs keep or how to store them; we make no shelf-life claim. What we could read about contamination: a study of 122 samples of two Chinese herbal teas found almost all contained pesticides, with about 40% of samples of some pesticides above EU permitted values, though the authors' health risk assessments were acceptable. [5] A study of Serbian herbal teas found toxic cadmium and lead below the detection limit. [6] A study of Malaysian herbal decoctions found boiling significantly reduced microbial contamination. [7] These are small local studies and do not describe every product.

What we do not give

We do not publish water temperatures, steeping times or amounts for every herb, because they differ by herb and product. For specific amounts, see EU monograph examples. We do not give home extraction instructions, and we do not cover storage of dry herbs because we found no source we could read.