All flavorists know these chemicals as USP grade and FDA approved food additives. Basic tobacco blends contain molecules of Acetyl Pyrazine, Carvone, Cinnamic Aldehyde, Damascone Beta, Ethyl Acetate, Ethyl Maltol, Ethyl Vanillin, Lialool, Menthol, Menthyl Acetate, Methyl Cyclopentenolone, Syringol, Tabanon, Tetramethyl Pyrazine, Trimethyl Pyrazine, and Vanillin. Welcome to food flavorings. Molecules like these are used to produce amazing flavors. For example, many tobacco flavors are made from two fruit molecules, which individually taste like fruit. I've tried very hard to get into this chemistry and have all of these chemical molecules. It's a true art and a science, and while I DIY, true flavorists are a very special gifted breed, much like perfumers. I'm glad someone can make my cinnamon Danish concentrates, that I can turn into one very nice ejuice. Do not worry when you see these chemicals, unless you see diacetyl (buttery), acetoin, or acetyl propionyl, which are approved food additives, but known carcinogens.
Here's an explanation of flavor from TPA:
"There are many approaches to experiencing the art of Flavor Creation. You might like to start out by experimenting with pre-made flavor concentrates. These concentrates are very easy for beginners to use, and we have lots of flavors to get you started. Flavor concentrates are blends of various materials, both synthetic and natural, that are usually diluted in a carrier liquid. The most common carriers for flavor are Propylene Glycol and its derivatives, Ethyl Alcohol, Vegetable Glycerin, and Triacetin. The flavor blends we offer are very concentrated, and are not meant to be ingested directly without diluting; they are meant to be used as flavoring agents for many types of applications. If you choose to learn about how these concentrated flavors are made, you will explore the different types of materials used in flavor creation described below. Essential Oils are obtained by distillation of flowers, roots, bark of trees, etc. These are the natural oils that are present in flowers, herbs, and woods. Distillates and juices of fruits and berries are also used, but usually can not be used to make very concentrated flavors because of the potential need for refrigeration The most commonly used type of flavor material is the flavor molecule. These are the molecules that are the "building blocks" of all flavors, and many of them are derived from natural sources. For example, natural orange essential oil is composed of molecules such as limonene and citral. Many of these molecules can be isolated from the complete oil by natural means such as fractional distillation The separation of a mixture (ex. an essential oil) into its component parts, based on each molecule's boiling point. These aroma molecules can be challenging, in that many of them have effects on a flavor composition that are not obvious when evaluating them separately. Just like with cooking, it is sometimes best to start with a known formula, then experiment by varying the proportions and introducing new materials. Some of these flavor molecules exist as liquids, and some are crystals and powders. Flavors can be created as either oil or water soluble, which can sometimes be a challenge when working with materials that lean strongly one way or the other! Water soluble means that a flavor will dissolve into water, or propylene glycol, or other mediums that are not oils. If a flavor is oil soluble, and you put a few drops into water, it will simply separate and float (or sink) and will not combine. So it is important to know which type of flavor material is right for your application. For example, cinnamaldehyde (cinnamic aldehyde) is a very important molecule used in all cinnamon flavors. But on its own it is not water soluble at all!"
