This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
This is another substance commonly used for coloring purposes. It is nearly identical with orseille. Its origin is vegetable, being prepared from the lichens of the same plant as litmus, having turned red by treatment with ammonia, and it works neither injury to the beverage nor its consumer. Most convenient is probably the tincture of cudbear, as it affords a good, substantial and natural-looking color misci-ble with syrup and beverages without cloudiness. Exhaust by maceration or displacement from two to four ounces of powdered cudbear with one pint of diluted alcohol. Used alone, this color gives a shade of red, closely imitating the color of raspberries or currants. For deep red, like blackberries, the addition of some caramel is all that is necessary.