On a daily basis, working behind the bar, I encounter all kinds of customers, and a significant portion of them are not used to coffee beans that are on the acidic side. Typically, the coffees with strong acidity are those that are roasted lighter, and indeed, some lightly roasted coffees have an acidity that is hard to accept. As a result, customers naturally get the impression that the lighter the roast, the more acidic the coffee will be.
But is that really the case? This depends on the sources of acidity in coffee and how these acids change during the roasting process.
● The acidic substances in green coffee beans include malic acid, citric acid, tartaric acid, chlorogenic acid, phosphoric acid, etc.
During the coffee roasting process, the sugars and organic acids in the beans begin to degrade or decompose into acids such as formic acid, acetic acid, lactic acid, fumaric acid, and conic acid, but as the roast degree deepens, these acids continue to degrade or evaporate.
During roasting, the stage where the acidity and concentration of acids change most dramatically is the development stage after first crack begins. From this perspective, the acids in coffee reach their peak at some point after first crack and then decrease due to thermal decomposition or evaporation.
In fact, at the start of first crack, organic acids such as formic acid and acetic acid in coffee are generated in large quantities, reaching their maximum near the end of first crack, and then begin to decrease. Meanwhile, organic acids originally present, such as citric acid and malic acid, are gradually decomposed as first crack progresses. Citric acid and malic acid taste brighter and more pleasant, while acetic acid and formic acid are highly volatile, taste very sour, and also smell sour, becoming irritating at high concentrations.
Moreover, after first crack begins, the sucrose in coffee is gradually consumed in reactions. So, in fact, coffee tastes most acidic during the medium-light roast stage, while at very light and light roast levels, because more sucrose is retained in the beans and the total amount of organic acids is not as high, it actually tastes like a soft acidity with a very natural sweetness. Some green beans that originally contain higher sugar content, if roasted to this stage, can even have a strong sweetness when drunk.
● I roasted a batch of Front Street Papua New Guinea washed Typica, divided into two roasts, and we tried to keep the yellowing point before first crack and the first crack point the same, only changing the development time after first crack.
The first batch was dropped at 1:20 after first crack at 190.5°C (mid-stage of dense first crack).
The second batch was dropped at 1:40 after first crack at 191.8°C (end of first crack).
Cupping results:
First batch: Soft acidity on the palate, then sweetness quickly follows. However, the aroma is relatively simple, with a slight ginseng-like note.
Second batch: Brighter acidity on the palate, higher acidity, sweetness appears later, more complex aroma with fruity notes.
So, it is not necessarily true that the lighter the roast, the more acidic the coffee will be. This involves the complex changes and combinations of various flavor substances during coffee roasting. However, overly light roasting will give coffee beans a raw, green, and astringent taste—this is beyond doubt.
● Recommendations for coffee bean brands that are on the acidic side
Fruity acidity and floral notes, as the signature flavors of medium-light roasted coffee beans, are deeply loved by people. Recently, a friend who is passionate about fruity acidic coffee asked Front Street for recommendations on coffees with natural floral and fruity notes. Since that's the case, let's go through and find some single-origin coffee beans with fruity notes to recommend~
1、Bright citrus acidity + white floral notes — Front Street Fruit Ding Ding Coffee Beans
The Fruit Ding Ding Cooperative has 300 partner smallholder farmers and is renowned for growing some of the best quality coffee in Ethiopia. The processing method also follows the most traditional washed method, and it is called by many "the last pure land of Yirgacheffe." Among the customers who come to Front Street for coffee, if they want a washed fruity coffee, the baristas at Front Street Coffee (FrontStreet Coffee) will prioritize recommending the Fruit Ding Ding Cooperative coffee on the bean rack. The washed Fruit Ding Ding Cooperative coffee not only lacks the heavy bitterness of traditional black coffee, but its fresh and bright citrus, lemon acidity, and jasmine fragrance make many coffee lovers fall in love at first sip.
2、Rich berry aroma + cherry tomato acidity — Front Street Kenya Little Tomato Coffee Beans
For those who are naturally fond of acidity, Front Street has always recommended this bean first, so in terms of fruity acidity alone, no other coffee can rival it. This Kenyan coffee's varieties are SL28 and SL34. Both SL28 and SL34 were selected after multiple breeding efforts. SL28 belongs to the Bourbon genetic group, carrying the bright character and rich acidity of the original Bourbon, while SL34 is genetically closer to Typica, with a milder acidity. Secondly, it uses the locally distinctive K72 washed processing method. The multiple soak washed model creates a clean yet solid fruity acidity. When made into iced coffee, Front Street Little Tomato offers dark berry flavors on the palate, along with full cherry tomato aromas. Drinking it chilled is very satisfying, making it a top choice for many friends when making cold brew.
3、Raisin + fruit gummy — Front Street Strawberry Candy
Compared to other fruity coffees, this bean has a somewhat special "background," as it combines two well-known producing regions in Central and South America: one is a honey-processed coffee from Costa Rica, and the other is a washed Geisha from Panama. To highlight its essence as much as possible, Front Street uses a medium roast, allowing it to show both orange-blossom honey charm and rounded sweetness when brewed. It is suitable for cold brew, pour-over, espresso, and other extraction methods, refreshing the palate on every sip.
4、Passion fruit acidity + blueberry sweetness — Front Street Colombia Big Belly Button
At the 2023 WBC finals, Australian competitor Jack Simpson used a coffee called Big Belly Button and showcased its rich juicy character through three different beverages, drawing attention to this somewhat unusual variety. Front Street Big Belly Button coffee comes from Colombia's famous Huila region, produced by Finca La Divisa, and uses a double anaerobic natural processing method, which allows the coffee cherries to successfully release enticing floral and fruity aromas. Each time it is brewed, it always carries rich notes of grape, orange, blueberry, and more.
5、Citrus acidity + honey pomelo tea — Front Street Butterfly
Butterfly is composed of three coffee varieties: Geisha, Caturra, and Catuai, all produced in Panama's famous Boquete, where well-known estates such as Hacienda La Esmeralda and Elida Estate are located. According to information Front Street found, in order to pursue yield in earlier times, the Geisha variety was planted mixed together with Caturra and Catuai coffee trees. Later, to highlight Geisha's characteristics, they began separately collecting the three varieties and using refined washed processing, then blending them together again when exporting. Since high-quality Geisha accounts for as much as 70%, the coffee naturally has obvious grapefruit, citrus notes, and light floral aromas, while the washed processing also gives the coffee a translucent tea-like quality.
The above content is compiled by CoffeeHunters, a coffee news website.
