The sun method involves floating flowerheads in a clear glass bowl filled with natural spring water. This is left in bright sunlight for three hours, then the flowerheads are removed and the energised water is mixed half and half with brandy.
The boiling method involves putting flowering twigs into a pan of spring water and boiling them for half an hour. The pan is then left to cool, the plant matter removed, and again the water is mixed half and half with brandy.
In both cases the resulting mix is known as mother tincture. This is diluted at the rate of two drops per 30mls of brandy to make the stock bottles sold in the shops.