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.
"Hot Ginger" is a familiar phrase, and denotes nothing more than a highly adulterated ginger extract with capsicum or tincture of capsicum. In regard to the effects of this capsicum or Spanish pepper, we refer to "Capsicum".
It will be noticed that in nearly all the Formulae for ginger ale, capsicum is found. Of course this is for the reason that a sufficient pungency to satisfy a popular demand cannot be obtained from ginger alone. That this is so is also plainly indicated by the well-known fact that a largely increased sale of capsicum has followed very closely on the increase in the use and sale of ginger ale and allied preparations. This unrestricted use of capsicum cannot be too severely condemned. Physicians and judges of fine quality ginger ale are opposed to its introduction, on the ground of being: unnecessary and hurtful.
Capsicum is an article whose use by carbonators should be more honored in the breach than in the observance. Its excessive presence in ginger ale irritates the coatings of the stomach to an abnormal degree. Notwithstanding this warning, however, some extract manufacturers still persist in its use, and, for an excuse, offer the request of bottlers for goods that are "strong," which is better than none at all. The strength of pure ginger is sufficient for all purposes, and the almost universal use of capsicum is of no credit to the trade. However, if it is desired to introduce capsicum, only a dash of it should be employed, which will he sufficient to have the warming and invigorating effect looked for.