How to Make A Cold Infusion
A cold infusion is a tea made with room-temperature or cool water instead of hot. It's slower, gentler, and for certain herbs it's actually the better way to get the medicine out of the plant.
Why cold?
Heat isn't always your friend. Mucilaginous herbs like marshmallow root and slippery elm are rich in the soothing, slippery compounds that coat and calm the gut, throat, and urinary tract. Heat breaks those compounds down, while cool water draws them out beautifully.
Aromatic herbs like lemon balm, peppermint, and rose hold their medicine in delicate volatile oils that boiling water can drive off. A cold soak keeps more of that flavor and fragrance in your cup. Cool water also pulls out fewer bitter compounds, so a cold infusion is often smoother and sweeter than the same herb steeped hot.
What you'll need
A clean quart mason jar with a lid
Dried or fresh herbs
Cool, filtered water
A fine mesh strainer or cheesecloth
How much herb
For a soothing, medicinal-strength mucilage infusion (marshmallow root, slippery elm): about ½ cup dried herb per quart of water.
For a lighter, everyday aromatic infusion (lemon balm, mint, rose, chamomile): about 2 to 3 tablespoons dried herb per quart of water. If you're using fresh herbs, roughly double the amount, since fresh plant material isn't concentrated by drying.
Steps
Place your herbs in a clean quart jar.
Add just enough water to moisten the herbs and let them sit for a minute.
Fill the jar to the top with cool water.
Cap it tightly.
Let it steep for 4 to 10 hours, shaking it now and then. Mucilaginous herbs do best with the full 8 to 10 hours, so overnight in the fridge is perfect.
Strain, and drink throughout the day.
Tip: For less mess, place the herbs in a muslin bag or tea ball and hang it near the top of the jar. As the plant releases its constituents, they sink and fresh water circulates up through the herbs, giving you a stronger, cleaner extraction.
Storage and safety
Because a cold infusion is never boiled, it spoils faster than hot tea. Keep it in the refrigerator and drink it within 24 to 48 hours. If it smells off, tastes sour, or turns cloudy or slimy in a way it wasn't before, compost it and make a fresh batch. Start with a clean jar every time.
When to skip the cold method
Most roots, barks, seeds, and medicinal mushrooms need heat to release their medicine, and are better made as a hot infusion or simmered decoction. Marshmallow root and slippery elm are the classic exceptions.
Herbs that love a cold infusion
Marshmallow root
Slippery elm bark (please choose sustainably sourced or cultivated, as wild slippery elm is at risk)
Alfalfa
OatStraw
RedRaspberry
Lemon balm
Peppermint
Rose petals or buds
Chamomile
Thyme
Always check with a physician before starting new herbs if you are pregnant, breastfeeding, taking medications, or managing a chronic condition.
Further reading
Mountain Rose Herbs: What Is a Cold Infusion? https://blog.mountainroseherbs.com/what-is-a-cold-infusion
Community Pharmacy: How to Make Herbal Teas and Infusions https://www.communitypharmacy.coop/blog/how-to-make-herbal-teas-and-infusions
