Tinctures are an easy way of taking herbs, as the herb is in a liquid form and preserved. Herbs whose active constituents are water soluble are made with 25% alcohol, in order to preserve the tincture. Other herbal tinctures are made with 45% or even 90% alcohol. Their strengths normally range from: one third of herb to the alcohol solution (1:3) down to one tenth of herb to alcohol solution (1:10).
To make a tincture add the herb into a container (such as a glass jar) cover with alcohol and leave in a cool dark place for 3 weeks, shake the bottle each day. After a few weeks the alcohol should have changed colour, strain off the herb and either repeat with more herb or bottle in a opaque bottle and store in a cool dark place.
The easiest type of alcohol to use for a home made tincture is vodka. With vodka it is fairly easy to make a 25% tincture with fresh herbs (as the water in the herb will reduce the percentage of the overall tincture), or a 45% tincture with dried.
To make half a litre of lavender tincture (strength 1:5, alcohol 45%) use 100 gm dried lavender flowers and 500 ml of vodka. Only use enough herb for the vodka to cover, you may have to use 50 gm initially and then repeat the process with the other 50 gm. For fresh herbs you will need a larger weight of herb due to the water content. For instance to make marigold tincture (strength 1:5, alcohol 25%) use about 200 gm of marigold flowers and 500 ml of tincture. With fresh herbs it is very likely the process will need to be done twice. Another way to make a strong tincture is to grind the herbs down before adding the alcohol, that way more herbs can be fitted into the jar.
A "Fluid Extract" is a term meaning a 1:1 ratio of alcohol and herb. This gives a concentrated extract.