Tag Archives: chemistry

Who’s afraid of chemistry? (by Paul) – Part 2.

Let’s get on to answering the question of part 1 why we don’t smell/taste during smoking what we smelled before in the tobacco pouch:

Boiling_pointWhen you look at the variety of additives for pipe tobacco, for example to search for those on Wikipedia, you find some difficult descriptions and properties of those additives. Either the natural thing or the artificial. The most important value for our answer is the boiling point of that molecule. If we look up vanilline, it says it has a boiling point of 285 °C (= 558 K [Kelvin] or 545 °F).

pipeNow, why is that Boiling Point so important? Well, a German friend has asked a chemical engineer to measure the temperature of smouldering tobacco in a pipe and found it to be approximately 500 °C (= 773 K or 932 °F). When we take a puff at our pipe, the temperature of the smouldering tobacco quickly rises to about 700 °C (= 973 K or 1292 °F) and then drops right back to 500 °C if we stop puffing. And that is a big part of our answer: the used additives in pipe tobacco are already evaporated. This because their boiling point is way below the temperature of our smouldering tobacco. As you will find out by searching the boiling points of other aroma molecules, whether fruits or drinks or whatever, most of these molecules have a boiling point between 190 °C and 300 °C (= 463 K – 573 K or 374 °F – 572 °F) and will evaporate during smoking. So we don’t smell the aromas.

That’s the main reason, in my humble and not-scientific approach, that we don’t recognize the aroma from the pouch during the smoking of the tobacco. But there are some aroma’s which seem to be recognizable while puffing at our pipe. Why is that?

Carbon atom

Carbon atom

Well, this takes us to another chemistry thing: how many carbon atoms are present in the molecule of such an aroma? Because carbon has a boiling point of 4554 °C (= 4827 K or 8229 °F), these carbon atoms will not evaporate. Instead they will burn or at least heat up. This will be detectable during smoking by our nose and it smells like “burning coal”, often described as “just warm air”. In short, the more carbon atoms an aroma has, the better you can recognize it.

Furthermore aroma molecules which are pentose or hexose molecules (respectively five or six carbon atoms in the molecule) or more, like vanilline with eight carbon atoms, are harder to evaporate. Because of the high boiling point of the bigger share of high temperature carbon atoms, they might be easier escaping our pipe-bowl before being evaporated. So, an aroma molecule with just three or four carbon atoms evaporates easier than a molecule with more carbon atoms.

Super-sweet BiBo tobacco

Super-sweet BiBo tobacco

There are examples of tobacco brands (like the super-sweet BiBo with oranges and chocolate aroma, Mediterraneo with peach-aroma and Memories of Tuscany with grape-aroma, all from DTM in Germany) which keep their aroma during smoking, down to the last ashes of our pipe. This is possible by using additives which contain more carbon atoms in the molecules. Or use can be made of alternative aroma additives which smell like (in the case of BiBo) oranges and chocolate, but have another molecular structure than the original orange or chocolate molecules.

Then there is another thing: the room-note. Why do people in the room smell more sweetness from our smoking then us, the pipe-smokers? Or why do we get the smell too, when we go out of the room for a little while and then return?

I think that’s because, although the smoking temperature is that high, some aromas will come out off our pipe bowl. This because they are connected to condensed water; air holds moisture and condenses while cooling down after being heated in our smouldering tobacco. So a small part of the aroma molecules “lifts along” with the moisture in the airflow which leaves our pipe between our smoke. And this might cause the nice room-note.

2769777dThe fact that the pipe-smoker doesn’t detect that room-note so intense as the other people in the room is also because his nose is right above the pipe. The smoke he takes in his mouth and nose is closer to the high temperature of the smouldering tobacco than someone who is present in the room but farther away from the hot tobacco.

Keep also in mind that we humans get easily used to an aroma. When you enter a cattle barn, you might find the aroma of cattle dung very much in your face. But after a few minutes you get used to it and you don’t experience it that strong as when you just entered the barn.

All this explains why we appreciate a tobacco much more when it is smoked very calmly. Smoking too quickly makes our tobacco burn too hot which evaporates aroma molecules. This also explains why some tobaccos change taste and aroma during smoking. The heat alters some molecular structures which brings out other aromas.

Enjoy your smoke,
Paul.

Who’s afraid of chemistry? (by Paul) – Part 1.

Paul (forum nickname Winslow Collector)

Paul

Paul is a prominent figure on the Dutch/Belgium pipe-smokers forum. He is a very well (self) educated man with a strong opinion about a lot of things that is he not afraid to express. He has around 240-250 pipes of which 180 are Winslows (often straight grains). Hence his forum nickname: Winslow Collector. He also has a passion for whisky and because of that he knows a lot about taste, flavours etc. A couple of weeks ago a forum member complained that when he smoked a pipe he did not taste and smell the same as when he sniffed his tobacco-pouch. Paul gave a very interesting answer which I never had read or heard anywhere before. So I asked him if he was willing to write a guest-post about the subject. And luckily he was:

Who’s afraid of chemistry?

celebrate-chemistryA lot of people are. Yet I would like to take you on a little trip about the chemistry in our tobacco. And don’t worry, it will be as simple as possible to understand. Even if you don’t have a university degree in chemistry. And surely I don’t have one, it’s just a big interest of me and I will try to explain some things by deducing this-and-that by thinking logically.

The idea to write something about the chemistry of our pipe-smoking hobby has its cause in a question of a fellow pipe-smoker: “Why does my sweet tobacco smells like what’s written on the pouch (i.e. “vanilla” or “cherry”) before I smoke it, but why can’t I smell and taste that during smoking?”

One of the key words in that question is “sweet”. However the following story is applicable for “natural” tobaccos, like Virginia, burley, latakia and what we call the English Blends. But it is mainly about tobaccos with a topping of some kind. Like fruits, vanilla, flowers, beverages (like wine, rum, whisk(e)y, grappa, etc.), nuts and other flavoured tobaccos.

pipe_756075Also important is the phrase “smell and taste”. Beware that what we taste is mainly done with our nose. Remember how bad your “taste” is when you have a severe cold. Our mouth has the restricted ability to define only five different tastes: salt, sour, bitter, sweet and umami (which is best described as savoury). These five are all the receptors in our mouth can distinguish. Our nose on the other hand has ten thousand times more receptors to distinguish aromas than our mouth has to define taste. Therefore you don’t taste strawberry. You taste something sweet and the aroma of strawberry and the “feel” of the texture in your mouth (connecting all this with some part of your memory) defines your sensation as strawberry. That’s pretty much all how we experience taste and this ends the physiological sidestep of the story.

So now we get to the phrase “why can’t I smell and taste that during smoking?” and this takes us into the chemistry.

Vanilla beans (Vanila Planifola) in their natural form. Biologically we have to refer to them correctly as berries.

Vanilla beans (Vanila Planifola) in their natural form. Biologically we have to refer to them correctly as berries.

All life forms on earth consist mainly of hydrocarbons, including plants. Our beloved tobacco is made of leaves from plants, as well as all kinds of additives to our tobacco’s, like fruits, vanilla, nuts, etc.

But what are those hydrocarbons? They are molecules, made out of the chemical compounds hydrogen, carbon and oxygen. Or as chemistry-people like to abbreviate: H, C and O. Do you remember those notations with all kinds of small numbers hanging to the letters?

Vanilla as we know it. After the beans are picked from their trees, they are heated with moisture and start fermenting. This is when the vanillin molecules in the beans start to develop. After drying the fermented beans we have these, almost black, vanilla sticks we might have in our kitchen to cook or bake cakes with. They are bursting of vanillin molecules which give us the nice vanilla aroma.

Vanilla as we know it. After the beans are picked from their trees, they are heated with moisture and start fermenting. This is when the vanillin molecules in the beans start to develop. After drying the fermented beans we have these, almost black, vanilla sticks we might have in our kitchen to cook or bake cakes with. They are bursting of vanillin molecules which give us the nice vanilla aroma.

Of course you do, you know that “water” is H2O, but did you know that glucose (the sugar in plants) is C6H12O6 ? And vanilla aroma comes from the vanillinin molecule, which is C8H8O3 in chemistry language? Well…, it is and I agree “vanilla” rolls of the tongue quite more easily than that formula. But “vanilla” doesn’t help us in trying to answer the question why we don’t smell/taste during smoking what we smelled before in the tobacco pouch.

Let’s try to find the answer with that example of the world’s most favourite aroma: vanilla. The vanilla aroma is so popular in food, drinks and tobacco, that there are simply not enough natural vanilla beans available. They are also quite expensive as additives and because we know what makes the vanilla aroma in these spices, we can build them chemically. We do this by artificially producing the right amount of hydrogen atoms, carbon atoms and oxygen atoms. Indeed: C8H8O3!

“We have the technology” is a famous TV-quote (don’t remember the program it was in) and this is very true in our world of food and drinks (and tobacco): we can chemically build any aroma we like. And not only “can” we, we are doing it. And because the molecular structure of the artificial built aroma is exactly the same as the one of the natural thing, the aroma is the same.

This entry continues in Part 2.