Dutch pink

On the subject of dutch pink, below is an extract from Hassal's book published in 1857 under the title Adulterations detected; or, Plain instructions for the discovery of frauds in food and medicine. It describes how to spot Dutch pink in tea.

Dutch Pink. -- Although called Dutch pink, this subtance is of a brigh yellow colour; it consists of a vegetable dye in combination with chalk or carbonate of lime. It is the yellow pigment most frequently used in this country in the facing of spurious green tea.

For its detection the following method should be pursued: -- An alkali should first be applied to the yellow dye, in order to determine, in the first place, whether it be vegetable or not: if it turn brown, there is no doubt about its vegetable character. In the next place, a minute portion of it should be examined under the microscope, with the view of ascertaining whether it is turmeric or not: if the cells of turmeric are not visible, and if it effervesce with an acid, there is no doubt that the dye is vegetable, and most probably Dutch pink.