Is SOE Americano Black Coffee Too Sour When It's Spoiled? Is It Normal for Espresso Beans to Have Acidity, and What Are the Reasons?

Why is my Americano sour?

"Ouch! Why is this Americano so sour? Has it gone bad?" Not at all. Some acidity in an Americano is perfectly normal, because coffee beans themselves carry rich acidic flavors. Those acidic qualities gradually diminish as roasting progresses. Most Americanos we drink daily are made with dark roast beans, but some varieties can still show noticeable acidity even when dark roasted.

While acidity in an Americano is normal, not all sour flavors are desirable. A vibrant, fruit-like acidity makes a memorable cup. Sharp or excessive astringency, on the other hand, points either to improper roasting of the beans or to problems in the extraction.

At FrontStreet Coffee, our Americanos are made with a blend of 30% Yirgacheffe coffee beans and 70% Sherry coffee beans. Although Yirgacheffe represents the smaller proportion of the blend, its acidity is amplified during pressure-based espresso extraction, adding a lively berry-like sweetness to the shot.

An Americano is simply espresso diluted with water. After dilution, the berry-like sweetness transforms into a bright, citrus-like acidity. In a hot Americano, as it cools and aromatic compounds dissipate, the acidity becomes more pronounced, which is why FrontStreet Coffee often reminds customers to enjoy their coffee while it is hot.

Iced Americanos, by contrast, are made by pouring espresso directly into ice water, which immediately lowers the coffee's temperature. That is why, with the same beans and extraction parameters, iced Americanos tend to be more acidic than their hot counterparts.

Why do improper roasting and extraction cause unpleasant acidity?

The difference between making an Americano with espresso and with pour-over coffee lies in the extraction method. Espresso uses pressure-based extraction and comes out more concentrated. Light roast beans that work well for pour-over may therefore not produce a good espresso or Americano. The increased concentration and intensity can in fact turn pleasant acidity into something unpleasant.

For this reason, when espresso becomes too concentrated or acidic, we recommend medium-dark roast blends designed specifically for espresso. FrontStreet Coffee currently offers four different espresso blends, all shipped within 5 days of roasting to ensure maximum freshness.

FrontStreet Coffee - Sunshine Blend: Ethiopia natural red cherry (30%) plus Honduras sherry barrel-aged (70%). Rich wine notes, vanilla cream, berry sweetness and roasted nut flavors.

FrontStreet Coffee - Specialty Blend: Colombia washed (30%) plus Brazil natural (70%). Nut, dark chocolate and caramel flavors.

FrontStreet Coffee - Commercial Blend: Robusta washed (10%) plus Colombia washed (30%) plus Brazil natural (60%). Nut, cocoa and caramel flavors.

FrontStreet Coffee - Foundation Blend: Yunnan washed (30%) plus Brazil natural (70%). Gentle fruit acidity, caramel and nut flavors.

FrontStreet Coffee Recommendation

If the brightness in your Americano comes from Yirgacheffe, FrontStreet washed Yirgacheffe is the classic place to start. Known for its white jasmine, bright citrus and lemon acidity and a tea-like body, it is a friendly introduction to the origin and a natural fit for both black coffee and blends.

For a different expression of the same region, FrontStreet Yirgacheffe Red Cherry is processed as a fully ripe, all-red cherry sun-dried lot, so it keeps the typical Yirgacheffe character while adding tropical fruit from the drying, with citrus-like acidity, a berry-juice quality, honey sweetness and a creamy smoothness.