Tea: The differences between infusions and decoctions
It seems nearly every culture around the world has their own rituals and traditions around tea- the best way to prepare it, the types of herbs and leaves used, the proper ceremony of serving it, and more. As herbalists, it is wonderful to be able to draw inspiration from these lasting traditions, but there are a couple of distinctions it is useful to make early on if your purpose is to create strong, effective medicine in the form of tea. Namely, what is the difference between an infusion and a decoction?
Tea infusions are made by boiling fresh water and pouring it over your fresh or dried herbs to steep anywhere from 4 minutes to overnight. This type of tea making is best for two types of plants: aromatic leaves and flowers whose essential oils you wish to capture and imbibe, and mineral-rich plants like nettles and oatstraw who need long overnight infusions to fully saturate the water with their nutritive elements. For aromatic leaves and flowers, we want to preserve their more delicate scents and flavors which are often what act directly on our nervous and digestive systems. These plants (think tulsi, rose, lemon balm, mints) may require just a few minutes of steeping in hot water to impart their medicine. Make sure to steep in a vessel with a lid, or a mug with a saucer placed over it to make sure the essential oils don't all escape into the air-- they are made of super light-weight molecules that are volatile and quickly disappear if you're not careful.
For mineral rich plants like nettles, oatstraw, raspberry leaf, etc, it is best to boil fresh water and pour it over the plants, and keep them covered and steeping for 8-12 hours for maximum benefit. Minerals are larger molecules that need time to dissemble and flow from plant to water, and by morning your infusion should be a rich broth-like supplement that is the perfect nourishment to hydrate with after a nights rest.
Some plants can go either way and you can get something different from them depending on what you need- for example chamomile. For sleeplessness and calming your nerves, you may prefer a fast and gentle infusion of the flowers as it is the volatile oils in the plant that exert such a strong effect on our sympathetic nervous system. However, chamomile is also a useful digestive bitter and if you are using it to calm stomach troubles then a longer steep is in order, as it extracts more of the plants bitterness.
Other plants with high mucilage do best with cold infusions, where you don't heat the water at all but instead steep the plant matter in cold water overnight. Marshmallow root and slippery elm bark are both good examples of this, and by morning your cold infusion will be thick and viscous, ready to coat any irritated mucous membranes along your digestive system.
Decoctions are made by boiling/simmering plants for anywhere from 15 mins to hours on end. They are used for tougher, high-resin plants, mushrooms and woody roots. There is no exact science to making a decoction but they tend to be much stronger tasting medicines than infusions because you are not as concerned here with capturing the delicate essential oils-- instead the bitterness, sweetness and acridity of plants is able to be revealed. Some flowers like calendula are high-resin and respond well to long simmering, often being thrown into slow cooked broths along with nourishing mushroom stocks. Some examples of commonly decocted plants are burdock root, dandelion root, reishi, and licorice. These plants need more time and heat to release their properties. If using fresh plants you can use less water because the plants themselves contain so much water, and if using dried you would compensate for that and add a bit more. Guidelines vary, but in general decoctions are often said to be ready when the water has reduced by half. It is best to keep the water at a simmer, and not allow it to reach a roiling boil.
Now that you know the different ways to make tea, you can get a lot more medicine out of the plants you are working with.
Kaaterskill Herb Exchange