What is acidity in coffee?
Coffee is many things. It can be a drink, a craft, and even a culture. You can take it black, with milk, blended, shaken, and stirred (sorry James Bond). However…it’s not a bean.
Coffee is a small stone-fruit that resembles a cherry. Inside these ‘cherries’ you can typically find two seeds. These seeds, after some processing, roasting, and brewing, are what the world runs on. The cherries grow on small, cultivated trees. While a wild coffee tree can grow as high as 40ft, it is typically kept at around 8ft for easy harvesting. Coffee consists of around 800 chemical compounds; like C8H10N4O2, C6H8O7, & C4H6O5.
Wait…coffee is a bunch of chemicals? Yes, just like you! But don’t worry, they sound less scary when you know that those strings of letters and numbers are just Caffeine, Citric Acid, and Malic Acid. These acids are paramount to the taste of coffee. During the roasting process, they react to the sucrose in coffee to make complex compounds that create sweetness and different flavors.
In specialty coffee, we mainly use one species of Coffee; arabica. You may have seen bags that say “100% Arabica” on them, which is a marketing technique as roughly 80% of all coffee is Arabica. The other 20% consists mostly of Robusta; a high-yielding, low-elevation coffee with around twice the amount of caffeine when compared to Arabica. However, it typically tastes like tar, dirt, and wood. As it has no desirable flavor, it takes up 0% of the Specialty Coffee Industry. All coffee is graded on a scale from 0-100. Anything that is 79pt and below is considered “Commodity Grade Coffee.” You can find this coffee in major grocery store brands, such as Folgers, Community, and Cafe Bustelo. Commodity-grade coffee also is typically produced through environmentally unfriendly practices and child & slave labor. Remember that next time you make your Target run.
However, around 3% of all coffee grown is graded 80pt and above. This is considered “Specialty Grade Coffee.” VCR and a lot of other great roasters only offer 85pt+ coffee, which is in the top 1.5% of all coffee.
Here is a quick breakdown of the two most prevalent acids in coffee, and how it applies to you.
Citric Acid
You are most likely familiar with citric acid, as it is in all citrus fruits; lemons, oranges, limes, grapefruit. However, you may not be aware that it is also a major compound that gives flavors like pineapple, strawberries, and raspberries. Citric Acid is very versatile, however can overpower a cup of coffee if the roast isn't balanced and the brew isn't evenly extracted. There are steps that we can both take to get the most out of these coffees.
What we can do
There are several different stages when roasting coffee, one of which is called the Maillard Phase (MP). This phase lasts from around 300° till First Crack; when the Development Phase begins. The length of the MP can help determine the sweetness and clarity of a cup of coffee. Longer time in this phase can bring out more sweetness, while a shorter time will allow for clearer, more distinct notes. Both play into the overall balance of the coffee. When we find some strong citric notes, we try to extend this phase a little longer so you can enjoy notes that taste less like lemon and more like lemonade.
What you can do
If you see a citric note on your bag, don't fear what you now understand! Just take measures not to under-extract the coffee. Try tightening up your grind size or extending your overall brew time. It's hard to over-extract light coffee, but it is extremely easy to do the opposite.
Malic Acid
You might be unfamiliar with the term Malic Acid, however you enjoy it's taste all the time! Malic Acid can be found in apples, pears, stonefruits (cherries, apricots, plums, etc..), bananas, and even watermelon. Malic acid is also used to create sour candies! Generally, malic acid is sweeter and softer than citric acid. The main downside is that, if underdeveloped, the coffee can taste soupy, or like tomatoes. Shockingly, that's not super desirable when drinking coffee.
What we can do
Many times with malic coffees, we like to lean towards clarity. We love tasting clear notes of Peaches, Apples, and Cherries. There is a lot of perceived sweetness from this type of acidity as well. We will always develop them just enough to get the maximum amount of flavor without giving you any soupy taste.
What you can do
Like any coffee, make sure you are using an appropriate amount of coffee to water. If your coffee is weaker, and more watery, these soupy flavors tend to show up more. So grab your scale and calculator, and make that little extra effort that results in a fantastic cup of coffee.
