Recipe for a 10% Propolis Tincture

Ingredients and proportions for a 10% propolis tincture:

100 g of raw propolis,
140 ml of water (preferably distilled or boiled and cooled),
360 ml of 95% V/V spirit.
Place the propolis in a glass container, pour in the water first, then add the spirit. Mix the ingredients and leave the container in a dark place for 14 days. Stir occasionally (shake).

The majority of soluble substances will dissolve into the solution within the first 2 days, but it is recommended to wait 14 days to obtain maximum benefits.

Heat accelerates dissolution, but do not overdo it. Room temperature is advised. Certainly no more than 30 degrees Celsius.

Finally, the tincture can be filtered through filter paper or decanted from the sediment.

This will produce a 70% ethanol tincture.
Alternatively, you can use simply 500 ml of 95% spirit without adding water. This will also result in a 10% tincture, but in 95% ethanol.
The difference is relatively small, but literature suggests that more desired components dissolve in 70% ethanol, while polycyclic aromatic hydrocarbons, which are not beneficial in excess in the tincture, dissolve to a lesser extent.

The numbers provided above might seem non-intuitive, however, it is important to consider that:

The content of ethanol-soluble substances in raw propolis: 50% (m/m)
Density of 95% ethanol: 811 g/dm³
Density of 70% ethanol: 856 g/dm³
When mixing ethanol with water, contraction occurs, meaning that mixing 140 ml of water with 360 ml of 95% ethanol will not yield a total of 500 ml, but only 488 ml.
Therefore:

500 ml of 95% ethanol (V/V) weighs 406 g
360 ml of 95% ethanol (V/V) weighs 291 g
488 ml of 70% ethanol (V/V) weighs 432 g
As a result of the above procedures, we will likely not achieve exactly a 10% concentration in the tincture. Theoretically, it should be 10.3% and 10.8% respectively. However, this will primarily depend on the exact content of ethanol-soluble substances in the used raw material.