The difference in the strengths of the extracts, taking into account synergy, is based on more than just the herb: liquid ratio.
The nature of the liquid is also important. 60% ethanol will remove a different package of constituents from the herb than will 45% ethanol which will again be different from 25% ethanol. Glycerin and other liquids create their own parameters.
When carrying out an extraction the concentration of the soluble components in the herb will always try to find equilibrium between the herb and the liquid. Therefore if we have a 1:3 extraction, 25% of the total soluble components will stay in the herb and 75% will transfer to the liquid (in theory). This means that if we start with 100g of soluble components in 300ml of liquid, we can theoretically achieve a finished product with 75g in 300ml or 0.25g of soluble matter per ml.
In a 1:1 using 100g of soluble components and 100ml of liquid then theoretically 50g will dissolve in the liquid leaving 50g in the herb. This leads to a product containing 50g in 100ml or 0.5g per ml. This shows that a 1:1 can only be twice as strong as a 1:3. The complicated part comes as there will be theoretical limits on the solubility of a particular component in a particular ratio of ethanol: water. For example hypericin is barely soluble in 25% ethanol but extremely soluble in 60% ethanol. However sugars, starches and proteins are usually more soluble in 25% ethanol than 60% ethanol.
This means that as the solvent is changed (i.e. the alcohol is increased) the nature of the extract changes. Most traditional tinctures have been made in spirits as this was the most convenient and available form of alcohol. The strength of the spirits has changed over the years but has usually been between 30 and 40% alcohol (100 degrees proof equates to 50% alcohol). This range allows a good mixture of the water soluble components and the alcohol soluble components to be extracted and so allows for synergistic action between components to occur.
The more pure the liquid (i.e. the closer to 100% alcohol or water) then the narrower the range of components removed from the plant will be. However these components are removed in far higher concentrations. “true" sediment in a tincture bottle is where the extraction is at the limits of the theoretically possible for the solvent and some of the dissolved components start to precipitate out. However another reason for sedimentation to occur is if the alcohol: water mix is made with hard water. As the alcohol is added to the water the water can no longer hold in solution the calcium and magnesium ions or the carbonate ions and these can precipitate out as lime scale.
