What coffee acidity means
Coffee acidity is the bright, lively, mouth-watering taste in coffee. It is one of the attributes cuppers score, next to body, sweetness, flavor and aftertaste. It comes from acids in the bean, and roasting changes it more than anything else: light roasts keep the most.
Acidity in this sense is a taste. How acidic a coffee measures on the pH scale is a separate question, covered below.
Acidity you taste vs acidity you measure
The two are related but not the same thing. Taste is about which acids are present and how they sit with the coffee's sweetness and body. Measurement is pH. Wikipedia's article on low-acid coffee puts the average pH of brewed coffee between 4.85 and 5.1, and a coffee counts as low acid above pH 5.5.
Coffee contains many acids, some pleasant and some not. Of particular interest to roasters are the chlorogenic acids, and Wikipedia's roasting article names breaking down the unpleasant acids as one of the key goals of roasting. World Coffee Research's Sensory Lexicon, which gives tasters a shared vocabulary of 110 attributes, includes sour among the attributes it gives reference standards for, so tasters can agree on what they mean.
How roast level changes acidity
| Roast | Acidity in the cup (Wikipedia's roast table) | Brewed pH (research cited on Wikipedia) |
|---|---|---|
| Light | Higher acidity; the very lightest is sharply acidic | About 5.0 |
| Medium | Acidity muted | Not given |
| Dark | Acidity diminished, nearly eliminated at Italian roast | About 5.3 |
The pH figures come from research from the Latvian Academy of Sciences that Wikipedia's low-acid coffee article cites, which found roast color the biggest driver of brewed coffee's pH. The same article reports a University of California, Davis study in which dark roasts, 250 °C for 21 minutes, cut chlorogenic acids by more than 99 percent compared with green beans.
Origin plays a part too. Wikipedia's coffee article notes that beans from different countries and regions differ in flavor, aroma, body and acidity, enough to tell them apart.
More or less acidity from Massachusetts roasters
Roasters we list describe how they handle acidity on their own sites (read September 27, 2026).
For bright, high-acidity coffee
- Broadsheet in Cambridge roasts as light as very light Nordic style.
- Barrington in Lee aims to show each coffee's own quality rather than roast flavor.
- George Howell in Acton sells several single estate coffees in a light roast.
- Equal Exchange sells organic Guatemala, Peru and Bolivia as light roasts.
For softer, lower-acidity coffee
- Speedwell in Plymouth roasts its Nine Bars espresso gently and longer, it says, to soften acidity.
- Gracenote in Boston roasts to a fuller profile than is common in specialty coffee.
- Indigo in Northampton roasts to Viennese, French and Italian levels.
- Esselon in Hadley offers French Roast, its darkest, and a Decaf French Roast.
Talking acidity with a roaster is easier when the roaster is down the road. Acoustic Java in Worcester runs a free public tasting every Friday at 10 a.m., a chance to ask about it in person. Why Massachusetts roasters matter.
Choosing your acidity in the club
The plan builder's roast level is your acidity dial. Light, described in the builder as fruit, flowers and plenty of snap, brings the most. Medium mutes it. Dark keeps it low. A two-bag box lets you have both, one light and one dark, each from a different Massachusetts roaster. $16.99 a bag, first bag free (you pay $7.99 shipping). Rate each bag and your ratings steer the next one. Pick your roast.
Related terms and sources
Related: light roast, dark roast, coffee cupping, balance, body.
Read September 27, 2026:
- Wikipedia, Low-acid coffee: pH ranges, roast and pH, chlorogenic acids
- Wikipedia, Coffee roasting: acidity by roast level, chlorogenic acids
- Wikipedia, Coffee cupping: acidity as a scored attribute
- Wikipedia, Coffee: acidity and origin
- World Coffee Research, Sensory Lexicon