Aromatic Components by Source
Based on their source, aromatic components can be divided into three sets:
Set One: Enzymatic By-Products (most volatile aromatics)
This set contains aromatic compounds that are the result of enzyme reactions that occur in the coffee bean while it is a living organism. They are the most volatile set, and most often found in the dry aroma of freshly ground coffee. When we discuss these aromatics, we talked in terms of flowery, fruity and herby. Here are the sub-categories of each (also noted on the Coffee Taster’s Flavor Wheel):
- Floral
- Sweetly Floral (jasmine, lavender, coffee blossoms) – an aromatic sensation commonly found in the fragrance of roasted and ground coffee beans. Created by highly volatile aldehydes and esters found in the gases (principally carbon dioxide) that escape from the newly ruptured cells of the bean fiber. Reminiscent of a fragrant flower, such as jasmine.
- Sweetly Herbal (wintergreen, tea rose)
- Fragrant
- Sweetly Spicy (cardamom, cinnamon, sandalwood) – an aromatic sensation commonly found in the fragrance of roasted and ground coffee beans. Created by highly volatile aldehydes and esters found in the gases (principally carbon dioxide) that escape from the newly ruptured cells of the bean fiber. Reminiscent of aromatic spices, such as cardamom.
- Carvone-like (caraway, dill, spearmint)
- Sweetly Camphoric (sweet basil, tarragon, coriander seeds)
- Anise-like (anise, fennel, basil)
This is an aromatic sensation commonly found in the cup aroma of the coffee brew. Create by highly volatile aldehydes and esters that become gases at the elevated temperatures of brewing. Noted as a sweet sensation reminiscent of a citrus fruit, or a tart sensation reminiscent of a berry fruit.
- Citrus-like
- Sweet Citrus (lemon, orange, tangerine)
- Dry Citrus (grapes, apples, olives)
- Berry-type
- Sweet Berry-like (cherry, apricot, strawberry, date)
- Dry Berry-like (cranberry, blackberry, boysenberry)
This is an aromatic sensation commony lfound in a brew’s cup aroma. Created by highly volatile aldehydes and esters that become gases at the elevated temperatures of brewing. Noted as either alliaceous-type sensations reminiscent of an aromatic vegetable (onion) or legume-type sensations reminiscent of a green vegetable (green peas).
- Alliaceous
- Onion-like (onion, chive)
- Garlic-like (garlic, leek)
- Leguminous
- Vegetable-like (garden peas, spinach, cabbage)
- Parsley-like (parsley, alfalfa, cucumber)
Set Two: Sugar Browning By-Products (moderately volatile aromatics)
These are composed of aromatic compounds that are the result of sugar browning (caramelization) that occurs during the roasting process. These are found in both the cup aroma of freshly brewed coffee and the nose (vapors) as coffee is swallowed. They are the primary means of distinguishing one coffee of similar origin from another. Found also in three sub-categories: nutty, caramelly and chocolaty.
The presence of sugar browning depends entirely on the roast process. Light-roasted coffee has a pronounced nutty character. Coffee that is roasted further the sugar molecules become a caramel character. Further heating reduces the caramel into a chocolaty character often found in full-roasted coffee. Any further heating begins to burn up the sugar, and these properties become less distinctive.
Nutty is an aromatic sensation commonly found in the nose of the brew. Created by moderately volatile aldehydes and ketones found in the vapors released as the brew is swallowed. Produces sensations associated with many roasted nuts.
- Nutty (roasted nut-like)
- Almond-like
- Peanut-like
- Walnut-like
- Malty (toasted cereal, grain-like) – an aromatic sensation normally found in the nose of the brew. Created by moderately volatile aldehydes and ketones found in the vapors as the brew is swallowed, producing sensations similar to toasted cereal grains.
- Basmati rice
- Barley-like
- Corn-like
- Roasted coffee
- Toast
Caremelly is an aromatic sensation commonly found in the nose of the coffee brew. Create by moderately volatile sugar carbonyl compounds found in the vapors released as coffee is swallowed. Reminiscent of sensations from candies or syrups.
- Candy-like
- Toffee-like (with butter)
- Licorice-like (with spices)
- Taffy-like (with salt)
- Pralines-like (with nuts)
- Hazelnut-like
- Syrup-type
- Molasses-like
- Maple Syrup-like
- Honey-like
Chocolaty is an aromatic sensation commonly found in the coffee brew’s aftertaste. Created by modertaley volatile pyrazine compounds found in the vapors released after the brew is swallowed. Reminiscent of either unsweetened chocolate or vanilla.
- Chocolate-type (with bitters)
- Baker’s Chocolate-like
- Dutch Chocolate-like
- Dark Chocolate-like
- Vanilla-type (with butter)
- Swiss Chocolate-like
- Custard-like
- Butter-like
Set Three: Dry Distillation By-Products (least volatile aromatics)
Aromatic compounds that result from the dry distillation (burning with intense heat) reaction of bean fiber are the least volatile and are most often found in the vapors (aftertaste) of freshly brewed coffee. The sub-categories of dry distillation include: turpeny, spicy and carbony.
Turpeny is an aromatic sensation commonly found in the coffee brew’s aftertaste. Created by slightly volatile hydrocarbon compounds and nitriles found in the vapor released after the brew is swallowed. Reminiscent of resinous sensations (similar to turpentine-like substances) or medicinal sensations (similar to camphor-like substances).
- Resinous
- Piney (pine sap, turpentine)
- Balsamic (juniper, chicory)
- Medicinal
- Cinoelic (oregano, rosemary, eucalyptus)
- Camphoric (camphor, cubeb, achillea)
Spicy is an aromatic sensation commonly found in brew’s aftertaste. Created by slightly volatile hydrocarbon compounds found in the vapor released after the brew is swallowed. Produces sensations reminiscent of wood-spice (cinnamon bark) or wood-seed (clove bud).
- Warming
- Nutmeg-like (nutmeg, celery seed, cumin, cedar)
- Pepper-like (black pepper, capsicum, ginger)
- Pungent
- Clove-like (clove, pimento, bay leaf)
- Thyme-like (thyme, savory, horsemint)
- Bitter Almond-like (bitter almond, peach kernel)
Carbony is an aromatic sensation commonly found in the aftertaste of dark roast coffee brews. Created by slightly volatile heterocyclic compounds found in the vapors released when the brew is swallowed. Reminiscent of phenolic sensations similar to a creosol-like substance or pyridine sensations similar to a burnt substance.
- Smoky
- Creosol-like (oil, tar, fat)
- Smoke-like (pipe tobacco, nicotine)
- Ashy
- Burnt-like (burnt, scorched)
- Charred-like (charred, ashy)
Bouquet: the Aromatic Profile
The total aromatic profile of a coffee brew is known as the bouquet. Created by the sensation of gases and vapors on the olfactory membranes. The result of the volatile organic compounds present in the fragrance, aroma, nose and aftertaste of the brew. There are four components of the bouquet.
1. Fragrance (dry aroma)
When coffee beans are ground, the bean fiber is both heated and ruptured, allowing carbon dioxide to escape. As it leaves, this CO2 extracts other organic materials, changing them into a gaseous state at room temperature. These gases, predominantly esters, form the essence of coffee’s fragrance. The fragrance is typically sweet smelling, resembling some type of flower. The fragrance also has some pungency, similar to that of a sweet spice.
2. Aroma (cup aroma)
When ground coffee comes into contact with hot water, the heat from the water changes some of the organic material from a liquid to a gas. These newly released gases (many of which are the larger molecular structure of esters, aldehydes and keytones) for the essence of coffee’s aroma. The aroma is the most complex mixture of gases in the overall bouquet.
3. Nose (nose-derived)
When coffee is slurped or vigorously sprayed toward the back of the palate, additional organic material (which is present in the brew in a liquid state) aerates and changes into a gaseous state. Also, any gaseous material previously trapped in the liquid is immediately released. These vapors (which are mostly carbonyl compounds) form the essence of coffee’s nose. Because most of these compounds were formed by a caramelization of sugars in the bean during roasting, the character of the nose most often resembles other products created by caramelization of natural sugars. These sensations can range from various candies or syrups reminiscent of caramel, to roasted nuts or toasted cereal grains. The character of the nose depends primarily on the degree of roast given to the grean beans.
4. Aftertaste
When the coffee is swallowed, some of the heavier organic material in the palate vaporizes. This set of vapors forms the essence of coffee’s aftertaste; literally meaning the sensation perceived after the taste sensation has diminished.
Because dry distillation of the bean fiber forms many of these heavier molecular components, they tend to have an aromatic character similar to wood or a wood by-product, ranging from turpentine to charcoal. The vapors usually have a pungency associated with a seed or spice, and they may have a note of bitterness, reminiscent of chocolate, due to the formation of pyrazine compounds during roasting.
Intensity
The terms that describe a coffee’s fragrance, aroma, nose and aftertaste comprise the bouquet’s variety, though the bouquet has one additional aspect: intensity. Intensity is a measure of both the fullness and the strength of the organic compounds making up the aromatic profile. Bouquets that are full and strong are described as rich. Bouquets that are full but lack intensity are described as full. An incomplete bouquet that lacks intensity is known as rounded. We characterize the absence of any bouquet simply as flat.
