Feel Good Tea, the chemistry of Coffee
Most of what we taste we actually smell. The only sensations that we pick up in our mouth are sweet, sour, bitter, umami and salty. Without its smell, coffee would have only a sour or bitter taste due to the organic acids. Try it with your next cup of coffee — hold your nose as you take your first sip.
The rich satisfying sensation of coffee is almost entirely due to the volatile compounds produced when we roast coffee beans.
The compounds that are formed in the roasting process are very similar to any other compound that is formed in the cooking process. The smell of baking bread is from compounds produced when a sugar reacts with a protein in what is called a Maillard reaction.
Not every scent is as welcoming as freshly baked bread, though. Our sense of smell has developed over millennia to detect dangerous compounds.
Flavourists and perfumists have developed a series of descriptors or words that are used to describe a particular smell. Using gas chromatography equipped with a sniffer port, chemists are able to smell individual compounds as they come off the gas chromatography column and apply a description to what they experience.
Words such as fruity, earthy, flowery, caramel-like, spicy and meaty are used to describe the odour of individual compounds. It is this complex mixture of volatile organic compounds that we can identify with a particular food. The smell of baking bread can easily be distinguished from the smell of cooking cabbage; a lamb roast from a pork roast.
Yet it is not one compound that is responsible for the odour that we experience but a complex mixture of hundreds of different compounds.
Source: www.lifehacker.com