Bitterness & Acidity in Coffee

Sometimes it is easier to describe what we don't want rather than what we do when it comes to selecting coffee. For many, the primary desire is to find a coffee that is not acidic or bitter. However, few individuals are aware of what causes acidic or bitter coffee and many confuse the terms.

Acidity is perhaps the most often confused term. This is because when coffee roasters speak of acidity they speak of a desirable attribute in a coffee's flavor. To a coffee roaster acidity describes the pleasant brightness a coffee displays on the taster's tongue. Acidity is similar to the idea of carbonation in a soda. We would not want a flat coffee just as we would not want a flat soda. Similarly, we would not want too much brightness in a coffee; rather, we would desire something that makes the coffee lively without an excessive bite.

The average coffee drinker however, tends to equate the term acidity to an acidic feeling in the stomach opposed to an impression on the palate. Instead of a desirable taste acidity is associated with a sour feeling occurring after the coffee is consumed. The latter of these acids are a result of the organic compounds of coffee being overexposed to heat and water causing quinic acidulation. Quinic acidulation can occur when a pot of coffee sits too long on a heated surface, allowing the brew to 'cook'. This is a common experience at countless restaurants that pay poor attention to coffee and serve a brew that has been allowed to burn for extended periods of time. Airpots and thermal carafes have eliminated quinic acidulation for quality-conscious restauranteurs.

Quinic acids can also be produced during roasting in machines that have poor heat transference. Unroasted coffee beans contain about 12% water by weight. This water must be driven off before the bean can be effectively roasted. Many poorly designed roasting machines are inefficient at driving off this moisture and they allow the still-wet beans to be exposed to high temperatures for excessive amounts of time. Kaladi Brothers Coffee utilizes the most efficient heat transference roaster available in the world. In our roaster, water is driven off the beans within the first minutes of the roast, thereby sharply reducing quinic acids from our roasted coffee.

Bitterness is easier to describe perhaps because it is one of the four primary taste sensations that our tongue perceives. The other three: sweet,salty, and sour are also experienced in coffee. As with all these characteristics there are both desirable and undesirable elements to the same taste. A coffee that displays too much of a salty characteristic would be undesirable, while a coffee that has some saltiness is often described as a soft or neutral coffee and can be quite pleasing. Too sour of a coffee causes us to pucker up while the right type of sour sensations can give a coffee a wine-like quality. The right stimulation of the bitter taste buds creates a pleasant bite to the coffee and can be most desirable.

Too often though, excessive bitterness is a result of improper grinding and brewing of coffee. When there is a lingering bitter characteristic from coffee it is an indicator that the coffee was too finely ground or too much coffee was used in the filter basket. Overly fine grind or too much coffee does not allow the water to flow properly and makes for a bitter tasting brew.

Finally, the brew rate of a coffee maker has a direct effect on bitterness and acidity. An ideal brewing time is less than four minutes. Most electric home brewers have inadequate water heating elements and result in too long of a brew time. Press pots, vacuum pots and pour-through filter carafes produce superior coffee since the water is heated in mass before brewing.

Great coffee is both a product and a process. Buying fresh, expertly roasted coffee is only the beginning. Ultimately, the result is a combination of right storage, correct measurement, and proper grinding for your brewing device.