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.
To give a yellow color to lemon essence and similar preparations, turmeric and saffron is commonly employed. We are not in favor of these colorings, as by judicious mixture with caramel or even a small admixture of red coloring any desired shade can be obtained. We append, however, two formulae for tinctures of turmeric and saffron for those who are in favor of or need them.
Turmeric ground, one pound; alcohol, diluted, from five to ten pints. Exhaust by maceration and percolation. This tincture shows a blue fluorescence, due to curcumin; it should be stored in the dark to keep off the influential action of light.