July 25, 2009, 12:13 PM Boulder Coffee Examiner Korina Felkers
Some people aren’t able to drink coffee because it bothers their stomach, but is it really the acid? In terms of the pH profile, coffee rates as low-acid, coming in at 4.5 – 6.0, depending on the coffee (A pH of 7.0 is neutral). Most regular sodas, diet sodas, orange juice and lemonade are significantly more acidic, at 2.0 – 3.0 pH.
Coffee has a multitude of chemical constituents; it’s more complex than wine. It is possible that the acids (of which there are many) are the culprit, but coffee does contain other components that are potentially irritating to the human gut. Despite all the research that’s been done, there is still much that is unknown about how the different elements in coffee react in our bodies.
Acidity in coffee is not related to its pH level, and is actually considered to be a desirable quality. Acidity refers to the flavor profile, similar to the sensations you experience when drinking wine: the tartness, brightness, zing or various regional influences in the bean, that hit both your tongue and your palate when you take a sip.
The acidity of a coffee is partly due to the growing region and partly influenced by the way a bean is processed and roasted. Coffee grown at higher altitudes and in volcanic soils tends to be higher in acidity, and is generally more highly prized. Brazilian, Peruvian, Kenyan and Ethiopian beans falls into this category. The coffees that are lower in acidity, such as Sumatra, are grown at lower elevations.
The roasting process is also very influential. The darker the roast, the lower the level of acid. An Espresso or French roast will be lower in acidity than an American or Viennese roast, for instance. A lower acid (dark) roast will also be “flatter”; remember, in coffee, acidity = greater flavor mosaic. Incidentally, the darker roasts, despite tasting stronger, also have a lower caffeine content.
Finally, the brewing method comes into play, too. Cold brewing your coffee is one way to dramatically reduce the acidity of your coffee.
So if it is the acids, or perhaps the caffeine, in coffee that are the tummy-torturers for you, there is hope. It could be that switching to a dark roast and/or cold brewing your coffee at home is just the ticket.
Glossary of Coffee Terminology - Copyright Zecuppa Coffee, LLC
Acidity, used as a coffee term, refers to bright, tangy, fruity, or
wine-like flavor characteristics found in many high grown Arabica coffees.
Coffee with high acidity is described as acidy, which has nothing to do
with amount of acid, or pH. Coffee actually has a relatively neutral pH of
between 5 and 6. When green coffee is stored for more than a year it will
have a perceptible loss of flavor and acidity. Also, acidity is reduced as
coffee is roasted darker.
A harsh sour taste. An acrid coffee can be described as tart, sharp, or acerbic.
The taste of brewed coffee vapors released after swallowing. Also called "finish", aftertastes can be chocolatey, burnt, spicy, tobaccoy, tangy, etc.
The taste term "alkaline" describes a dry taste sensation mostly at the back of the tongue. While somewhat bitter, an alkaline taste is not necessarily disagreeable and is characteristic of many dark roasts and some Indonesian coffees.
Coffee aroma is the fragrance of brewed coffee and is closely related to
coffee flavor. Without our sense of smell, flavor would be limited to the
tongue senses of sweet, sour, salty, and bitter. Many nuances of a coffee
are reflected in the smell, or "the nose". Subtle floral notes, for
example, are experienced most clearly in the aroma, particularly at the
moment when the crust is broken during the traditional cupping process.
Typical coffee aromas include floral, winey, chocolatey, spicy, tobaccoy,
earthy, and fruity. Coffee aroma is also experienced after drinking the
coffee when vapors drift upward into the nasal passage. This "retro
nasal" aroma is responsible for much of a coffees aftertaste. A coffee's
aroma is highest shortly after roasting and then declines rapidly. Coffee
freshness, including aroma, can be maintained for months if placed in
proper storage immediately after roasting.
Coffee odor similar to that of an ashtray or fireplace. An "Ashy"
aroma indicates a dark roast, and is not necessarily a negative attribute.
Ashy coffees generally have a carbony flavor.
Drawing coffee brew into the mouth by vigorous suction to spray it
evenly across the tongue releasing vapors. Aspiration helps cuppers attain
a better sensory evaluation of a coffees nuances.
A dry, sour, salty, and generally disagreeable sensation detected mostly at the sides of the tongue.
A taste characteristic of coffee stored too long in burlap (jute) bags,
causing the coffee beans to acquire a straw-like coffee bag flavor. Also
used to describe light roasted coffee with mildewy
Flat, dull, and uninteresting coffee. A baked flavor may be caused by
roasting too slowly. Coffee roasted in a drum roaster for much more than
about 17 minutes will likely be burnt or have a baked
A balanced coffee may be complex, but does not have any overwhelming
flavor or aroma characteristics. For example, Yemen Mocha is typically bold
and flavorful, but is also well balanced. In contrast, Kenya AA, generally
has a dominating wine-like fruity flavor. A well balanced coffee has
flavors that can be sensed evenly across the tongue. Blending several
different coffees together, if done correctly, can create a flavorful and
balanced coffee. Balance, however, is not necessarily a positive taste
attribute, since some people prefer coffees with particularly strong flavor
A harsh, generally unpleasant taste detected mostly in the back of the tongue. Bitterness is characteristic of over-extracted, defective, or extra dark roasted coffees.
The physical mouth feel and texture of a coffee. Full bodied coffees
have a strong, creamy, and pleasant, mouth feel. A coffees body (light,
medium, or full) is its thickness due to the amount of dissolved and
suspended solids and oils extracted from the coffee grounds, and may range
from thin and watery to thick and creamy.
The aroma of freshly ground coffee.
A bread-like, or grain-like, aroma. Insufficiently roasted, sour
tasting, coffee will often have a bready aroma. Bready coffees may also be
described as "green" or "beany".
Coffees with a pleasant, almost tangy, flavor. Bright coffees may also
be described as having a wine like acidity.
A salty taste often caused by continuously heating coffee after brewing
is complete. Brewed coffee that sits on a burner overnight is likely to
A flavor and aroma characteristic of candy or syrup in which sugars have
oxidized and become caramelized. Coffee beans contain sugars which
caramelize during roasting and, if not burned, may be detected as caramelly
notes in the cup.
The flavor and aroma characteristic of burnt food, or burnt wood.
Carbony flavors and aromas are often used as an indication of roast degree
when cupping darker roasted coffees. Also called "burnt" or
An herb used as a coffee substitute and to flavor coffee. Chicory, or Cichorium Intybus, has been used as a coffee additive for centuries, both to enhance flavor of coffee and to stretch coffee supplies. In New Orleans, Louisiana, many have developed a preference for chicory coffee.
The taste or aroma of chocolate. Coffees rarely have a very strong chocolatey flavor or aroma, but some Central American and Yemeni coffees have a distinct chocolatey aroma and a slightly bitter-sweet chocolatey taste.
The aroma and taste of ripe citrus fruit. Citrus notes are often found in coffee, which is not surprising considering the fact that coffee beans are the seeds of coffee cherries. Coffees with flavor characteristics of unripe citrus are described as "sour".
Flavorful, but without any pungent or unusual flavors.
The array of flavors and flavor shifts experienced when smelling and
tasting a coffee. While not necessarily a positive attribute, complexity
can sometimes be gained by blending one coffee with another or by blending
a dark roast with a light roast. Some excellent single origin coffees are
by themselves both complex and balanced, but agreeable complex flavors are
most often achieved by blending two or more complimentary single origin
The layer of saturated coffee grounds that floats to the surface when cupping (tasting) coffee. As part of the traditional coffee cupping method, called "breaking the crust", the grounds are agitated to release trapped vapors allowing the cupper note the coffees unique characteristics. The crust is then scooped out with a spoon before tasting the brewed coffee.
The aroma characteristic of fresh earth, wet soil, or raw potatoes. While not necessarily negative characteristic, earthiness may be caused by molds during the processing of harvested coffee cherries. Earthy notes, for example, are commonly found in semi-dry processed coffees from Indonesia.
A sour and oniony taste characteristic of over-fermented coffee. After de-pulping coffee cherries, which removes the skin and some attached mucilage (pulp), the separated beans will still have a significant amount of pulp attached. The remaining pulp is often loosened by fermentation, allowing it to be washed away prior to drying. If fermentation is not stopped as soon as the remaining parchment (husk) is no longer slimy, and has a rough texture, the coffee may acquire a ferment flavor.
Lacking flavor and aroma.
The scent of flowers including honeysuckle, jasmine, dandelion and
nettles. Mildly floral aromas are found in some coffees and are generally
perceived along with fruity or herbal notes.
The aroma and taste of fruit. Many coffees have fruity notes, which is
not surprising considering that coffee beans are seeds of a fruit (coffee
cherries). A coffees acidity, or wine-like brightness, is often related to
fruit, or citrus. Professional cuppers are careful to not use the term
"fruity" when describing the aroma of unripe, or over-ripe,
Aroma associated with freshly mowed green grass, herbs, green foliage,
green beans, and unripe fruit. A grassy aroma, also called green, herby, or
herbal, is characteristic of sour tasting under-roasted coffee beans and
under-dried or water damaged coffee beans.
Pungent and disagreeable, such as a low quality bitter Robusta.
An aroma associated with freshly mowed lawn, green grass, herbs, green foliage, green beans, and unripe fruit. Herbal characteristics are typical of coffees not fully dried to the usual 10% to 12% moisture content during processing. An herbal aroma is also called green, grassy, or herby.
The smell or taste of hide (leather). Hidey notes, for example, may be
found in some east African coffees.
A taste characteristic of freeze dried instant coffee. Many find the taste of instant coffee objectionable. Ironically, instant coffee is commonly served in Colombia and Brazil, both large volume coffee exporters.
The aroma of malt. Often used together with Cereal and Toast-like to include the aroma of cereal, malt, and toast. "Cereal", "Malty", and "Toast-like" describe grain-like aromas and flavors of roasted grain (including roasted corn, barley, or wheat), malt extract, freshly baked bread, or toast.
The smell of medicine, or iodine. A medicinal flavor with notes of iodine which can result from cherries drying while still on the coffee plant. Medicinal flavors cannot be hidden well by blending.
Balanced and mild, without strong tastes or aftertaste. Medium roasted,
low grown (less than 4000 feet) Arabicas, for example, generally have a
Neutral coffees do not have a predominant taste sensation, but may still
have a pungency felt by the tongue and are often used in blending. Coffees
from Brazil and Colombia, for example, commonly have a neutral
The aroma and taste characteristic of a coffee sensed by the nose,
especially when exhaling coffee vapors after swallowing.
The aroma and flavor characteristic of fresh nuts. Coffee cuppers are
careful to avoid using the term "nutty" when describing coffee with taste
or aroma characteristics of rancid nuts or bitter almonds. Coffees from
South America commonly have a nutty flavor.
Flavor characteristic of onions, and often associated with the use stagnant water when processing coffee by the wet method. Oniony characteristics are often avoided by recycling the pulping water during processing.
A taste characteristic of coffee stored in paper bags or prepared using low quality filter paper.
Coffee from a previous years harvest. Past crop, old crop, old, or
oldish are also used as a taste terms to describe coffees stored for more
than a year. Past crop coffees tend to have a woody, strawy, or hay-like
flavor and less acidity.
An unpleasant bitter taste similar to fresh green peas.
Professional coffee cuppers may describe flavors detected by the tongue (primary tastes), and flavors detected through the nose (secondary tastes). Primary tastes are salty, sweet, sour, and bitter. Taste buds are located on our tongues, and while many subtle tastes can be recognized, there are only four distinct tastes (salty, sweet, sour, and bitter). Each taste bud contains between 50 and 100 taste cells, and each taste cell has receptors. While receptors are capable of recognizing all tastes, some tend to recognize sour foods and are usually located around the sides of the tongue. Sweet and salty foods are usually tasted best near the end of the tongue. Bitter foods are usually tasted at the back of the tongue. The middle of the tongue usually has no taste buds.
A peanut-like flavor that results from processing unripe or
underdeveloped coffee beans.
The terms "rancid" and "rotten" are used to describe characteristics of decomposing coffee. Professional coffee cuppers are careful to not describe a strong and unpleasant aroma as "rancid", if there are no other signs of deterioration.
The aroma and flavor characteristic of hot tires or rubber bands. A rubbery characteristic, while not always negative, is highly recognizable in some coffees, especially fresh Robustas.
Roasted coffee with burn marks caused by inadequate tumbling or by roasting too hot. Also called "tipped" or "charred". Scorched beans may look completely roasted, but are likely to have soury and bready flavors.
A taste characteristic of balanced coffee without any pronounced tastes or aftertastes. Also called round, rounded or soft.
An excessively sharp, biting and unpleasant flavor (such as vinegar or
acetic acid). Sour or soury flavors are sometimes associated with the aroma
of fermented coffee. A sour taste can be caused by overripe or already
fermenting cherries, or by improper fermentation where yeasts and alcohol
form vinegar-like acids To avoid this defect, coffee still in its parchment
(husk) is washed immediately after fermentation when the parchment coffee
is no longer slimy and has a rough texture. Soury flavors are often
confused with acidity, which is the slightly tangy sensation associated
with bright coffee flavors.
The aroma of sweet spices such as cloves, cinnamon, and allspice. The term "spicy" when describing coffee does not include the aroma of savory spices such as pepper, oregano, and curry.
An unexpected off-flavor not clearly defined by usual taste categories. Too much pulp in fermenting parchment, for example, will produce tainted coffee.
The aroma and flavor of fresh tobacco in brewed coffee. A tobacco-like taste is not necessarily disagreeable and is found in various specialty coffees throughout the world. A tobaccoy taste or aroma should not be confused with characteristics of burnt tobacco (ash).
The combined sensation of smell, taste ,and mouth feel experienced when drinking wine. A winey taste is generally perceived along with acidy and fruity notes. Often used incorrectly to describe a soury or over-fermented flavor.
A taste characteristic of old coffee. Woody coffee has a smell of dry wood, an oak barrel, dead wood, or cardboard. This defect results when beans are improperly stored for an extended period of time. Coffees stored at low altitudes in high temperatures and humidity (as in many ports of shipment) tend to deteriorate quickly and become woody. All coffees can become woody if stored long enough.