This helps explain why our mixture easily crystallizes, especially when the container is about three quarters full. The mixture is acidic with an average pH of 3.9, but an exceptionally wide range of 3.4 to 6.1 is possible. Part of a logarithmic scale, a pH of 6.1 is 500 times less acidic than 3.4. The main acid is gluconic acid, created by the enzymatic oxidation of a COH group in glucose.
Gluconic acid helps enhance its flavour, and it is in the company of at least 26 other organic acids including a small amount of acetic acid (the same acid found in vinegar), succinic acid, citric acid, and 18 of the 21 existing amino acids. Overall the acidic composition plays the role of a a preservative and contributes to its aroma. The addition of our mixture at a concentration of 25% to a 0.15% citric acid solution resulted in almost a 75% decrease in sourness perception.
But how can the pH vary so widely? It's because the raw material for its production is highly variable. Some of the mixtures are made from a single source, but most commercial products are not. Our mystery mixture's volatile compounds are related to their botanical origin, and many of them are their characteristic markers. The signature can be obtained by using SPME-GC/MS methods. (Hold your breath; SPME-GC/MS stands for solid-phase microextraction-gas chromatographic-mass spectrometry ) For instance, if the source is eucalyptus, then the volatiles include acetoin and nonanol. A citrus origin for the mixture, on the other hand, will feature hotrienol, limonene and lilac aldehyde.
All this talk about acids and terpenes may lead to the false impression that they are our mystery mixture's major components. But they are not. The mixture's main components are fructose and glucose, usually about 40% of each, but if the source is tupelo (the pepperidge tree, not the town in Missouri) then it could be a 50-30 blend.
Due to the possible presence of Clostridium botulinum spores it should not be given to infants, even if the mixture has been pasteurized. I love adding it to my coffee. Before cane sugar became ubiquitous, the mixture was the most common sweetener. From the Cambridge edition of the King James Bible:
Unto a land flowing with milk and honey: for I will not go up in the midst of thee; for thou art a stiffnecked people: lest I consume thee in the way.
And at the outset, I was alluding to the bizarre Charles Manson version:
It was exciting, amazing stuff Charlie was teaching, and we'd sit around him for hours as he told us about the land of milk and honey we'd find underneath the desert and enjoy while the world above us was soaked in blood.
Sources:
Journal of American Dietetic Association
Ischayek JI, Kern M., 2006 Aug; 106(8):1260-2
N a t i o n a l H o n e y B o a r d F o o d T e c h n o l o g y / P r o d u c t R e s e a r c h P r o g r a m
Food Chemistry 103 (2007) 1032–1043 Analytical, Nutritional and Clinical Methods
A review of volatile analytical methods for determining
the botanical origin of honey