7 min read
It is basically a tie. Black coffee sits around pH 4.85 to 5.4, and black tea around pH 4.9 to 5.5, so neither is meaningfully more acidic than the other. If you want the gentlest cup, green tea is the least acidic of the common choices.
The more useful question is what that acidity does to your stomach and teeth, and which coffee is easiest on a sensitive system. Let me walk through the numbers, clear up one myth, and show what actually helps.
Coffee vs tea, by the numbers
When we say a drink is acidic, we mean it carries compounds, like chlorogenic acid and quinic acid in coffee, that taste a little sour or tangy. The pH scale puts a number on it: 0 to 14, where 7 is neutral, anything lower is acidic, and anything higher is alkaline. It is also logarithmic, so each whole step is a tenfold change. A pH of 4 is ten times more acidic than a pH of 5.
| Drink | pH range | How acidic |
|---|---|---|
| Black coffee | 4.85 to 5.4 | Moderately acidic |
| Black tea | 4.9 to 5.5 | About the same as coffee |
| Herbal tea | Varies widely | Hibiscus very acidic, chamomile near neutral |
| Green tea | About 6 to 9 | The gentlest common option |
So the headline is almost a non-answer: coffee and black tea are neck and neck. The bigger swings come from what you add and how you brew, which is where the differences you can actually feel show up.
The green tea myth
You will see it repeated everywhere: green tea has a pH of 10 and is therefore alkaline, many times less acidic than black tea. It makes for a tidy infographic. It is also not true.
A pH of 10 would put green tea up near hand soap and baking soda, which anyone who has tasted it knows is wrong. Brewed green tea is the least acidic of the everyday teas, but it lands roughly around neutral. Sources disagree on the exact figure, with tea specialists often citing a range closer to pH 6 to 7 and other references stretching toward 9. Gentle, yes. Soapy and alkaline, no.
Why it matters: if you switched to green tea expecting an alkaline drink that neutralizes acid, that is not what you are getting. You are getting a milder, near-neutral cup, which is still a good choice for a sensitive stomach, just for the right reason.
What acidity does to your stomach and teeth
Despite the reputation, there is no solid evidence that coffee or tea damages a healthy stomach. A 2019 study of more than 1,800 people found that drinking coffee, with or without cream, was not associated with GERD, acid reflux, or erosive esophagitis, and reviews of tea reach the same conclusion. What both drinks can do is stimulate stomach acid, so if you already have a sensitive stomach, you may feel them more than someone who does not.
Teeth are the murkier story. Their acids can contribute to enamel wear over time, and both stain, but moderate drinking is not clearly harmful. This is one spot where a less acidic option earns its keep.
The acidity is real. The idea that it is quietly wrecking a healthy gut is mostly not.
This is general information, not medical advice. If you have reflux, ulcers, GERD, or ongoing stomach or dental pain, acidity is only one piece of the picture, and a doctor or dentist who knows your history is the right person to weigh in.
If acidity bothers you, here’s what helps
You do not have to give up coffee to drink gentler. Three levers actually move the needle: brew method, roast, and origin. Cold brew tends to come out smoother and a little less acidic than the same beans brewed hot. Darker roasts usually sit slightly lower in acid than light roasts. And some origins are naturally mellow, especially low-grown, wet-hulled coffees like Sumatra.
If you want to go the origin route, I rounded up the mellow, low-acid options in our best Sumatra coffee guide, and the science behind cold brew explains why the cold method tastes so much smoother.
The flip side: both come with perks
Acidity aside, coffee and tea are among the more studied drinks on the planet, and the long-term picture is reassuring. A large 2016 umbrella review found that moderate coffee drinking, around three cups a day, was associated with lower mortality from several causes.
Tea holds up well too. A UK Biobank study of around half a million people found that drinking two or more cups a day was associated with a 9 to 13 percent lower risk of death from any cause.
One honest caveat: these are observational associations, not proof that the drink itself causes the benefit. People who drink moderate coffee or tea differ in lots of ways from people who do not. It is a reassuring pattern, not a prescription, and more is not better.
Quick answers
Is coffee or tea more acidic?
They are remarkably close. Black coffee sits around pH 4.85 to 5.4 and black tea around 4.9 to 5.5, so neither wins by much. Green tea is the least acidic of the common options.
Is green tea really alkaline?
No. The popular pH 10 claim is wrong. Brewed green tea is the gentlest common tea, roughly neutral, somewhere around pH 6 to 9 depending on the source. Mild, not alkaline.
Do coffee and tea cause acid reflux or hurt your stomach?
For most people, no. A large study found coffee, with or without cream, was not linked to GERD or reflux, and the same held for tea. Both can stimulate stomach acid, so sensitive stomachs may still react.
What is the least acidic coffee?
Cold brew is usually gentler than hot, darker roasts edge out lighter ones, and mellow origins like Sumatra are known for low acidity. Some brands also process coffee specifically to cut acid.
Are coffee and tea bad for your teeth?
The evidence is mixed. Their acids can wear enamel over time and both stain, but moderate intake is not clearly harmful. Cold brew may be gentler for sensitive teeth.
The bottom line
Coffee and black tea are about equally acidic, both near pH 5, so you cannot pick one over the other to dodge acid. Green tea is the gentlest, just not the alkaline miracle the internet promises. For a healthy stomach, neither drink is the villain it is made out to be, and both come with real long-term upsides. If acidity genuinely bothers you, reach for cold brew, a darker roast, or a naturally mellow origin before you give up the cup entirely.
Sources
- Poole R, et al. Coffee consumption and health: umbrella review of meta-analyses. BMJ, 2017;359:j5024.
- Inoue-Choi M, et al. Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank. Ann Intern Med, 2022.
- Wei Y, et al. The role of tea and coffee in the development of gastroesophageal reflux disease. Tzu Chi Med J, 2019;31(3):169-176.
- Fujioka K, Shibamoto T. Chlorogenic acid and caffeine contents in various commercial brewed coffees. Food Chemistry, 2008 (brewed coffee pH 4.95 to 5.99).
