The Role of Essential Oils
The fragrance and taste of any spice or herb comes from the essential oils that are carried in the plant’s cells. In some plants,(like the crocus plant) the essential oil is concentrated in one area. Most spices contain a number of essential oils like zingerone, benzaldehyde, limonene, etc. Hence, the flavor is considered complex.
Some plants contain similar oils but in different concentrations, like cinnamon and clove. Each contains cinnamic aldehyde and eugenoil among other oils. However, cinnamic aldehyde is primarily responsible for cinnamon’s flavor and eugenoil is the key flavor element of clove. Therefore, they echo each other’s flavor notes and are often combined in cooking. Interestingly, if you were to taste a droplet of pure cinnamic aldehyde, it wouldn’t taste like cinnamon. This complex flavor signature requires the cinnamic aldehyde oil to be a part of the mixture that contains the other naturally occurring oils of the cinnamon bark before the true cinnamon taste can be fully realized.
In other instances, there are spices that come from different botanical sources but strangely mirror each other’s flavor composition. This is due to a similar composition and concentration of essential oils. A notable example of this phenomena is Star Anise and Anise Seed.
Star Anise is the bud of an evergreen tree and Anise Seed a ground plant. Both contain similar amounts of anethole, methylchavicol and anisaldehyde and can be substituted for each other or used in tandem in culinary applications.