Decoctions

Decoctions are made from the more fibrous or woody plant parts, such as the roots and bark, twiggy  parts, and some seeds and nuts. It's a little harder to extract the constituents from these tough parts, so a slow simmer is often required. After, add the spent herbs to your compost. A decoction require more energy for their precious constituents,  including minerals, to be extracted.

Basic steps:

Method 1:

1. Place 4 to 6 tablespoons of dried herb (or 6 to 8 tablespoons of fresh herb) in a small saucepan. Add 1 quart of cold water.
2. With the heat on low, bring the mixture to a slow simmer, cover, and let simmer for 25 to 45 minutes. (the length of simmering time and the amount of herb you use will affect the strength of the tea). For a stronger decoction, simmer the herbs for 20 to 30 minutes, then pour the mixture into a quart jar and set it aside to infuse overnight.
3. Strain and drink.

Method 2:

1. Put cold water to boil.
2. Add 1 ounce of herb per quart of water, reduce heat, cover, and simmer for about 20 minutes. For large or whole roots, you can simmer for up to an hour. 
3. Be sure to keep the heat as low as possible and the cover on, as many constituents, such as essential oils can be lost through evaporation. 
4. After being simmered, the herbs can be strained out immediately or left to steep overnight.

Note: Some people prefer to simmer the tea down to concentrate its properties even further. In this case, smaller dosages will be needed.

Decoctions are so potent that a serving size can be much less than for an infusion. An adequate portion would be 1/4 to 1 cup of tea.