This section is from the book "Monograph on Flavoring Extracts With Essences, Syrups, and Colorings", by Joseph Harrop . Also available from Amazon: Monograph On Flavoring Extracts With Essences, Syrups And Colorings.
Alcohol being the universal menstruum for the preparation of flavoring extracts, we will first consider the various kinds found on the market, and will call them:
First - Ordinary Alcohol.
Second - Middle Run or Deodorized (?) Alcohol.
Third - Cologne Spirit, True Deodorized or Atwood's Alcohol.
Ordinary alcohol is the alcohol in common use. It is the officinal alcohol of the pharmacopoeia, of 94 per cent. strength, the same as is recognized by the United States government, the alcohol of commerce of to-day.
It is readily distinguished by its alcoholic(?) odor, which is due to the presence of fusel oil, and, although of the proper alcoholic strength, we consider it unfit for use in the manufacture of flavoring extracts.
This alcohol is that which is kept separate from the first and last which runs from the still in its manufacture, and contains much less fusel oil than either of those portions. It is far better suited for general use (except technical), than the ordinary alcohol. It is the article usually furnished by the wholesale trade when deodorized is ordered.
It can be used in the manufacture of flavoring extracts with moderate success, but is not pure enough for a first class product.
This is the alcohol of alcohols. To get this is to get the best. Our advice is, be sure you get it. When mixed with oils or flavorings of any kind whatever, it is perfectly submissive. It does not speak up, by its presence, and say I am here, I, king alcohol; no, there is no fusel oil on which to base any such presumption. Your flavoring alone will speak; it alone has precedence.
Note - "Perfumers' Alcohol can now be had which, it is claimed, is very much superior to cologne spirit, as the purest alcohol obtainable was formerly called. It is termed perfumers' alcohol because it was found necessary to prepare a very high grade of alcohol for those who need a solvent for fine odors, on the score of economy, and to insure greater excellence of product."
* See page i, Pubs. Dept.