Coffee is one of the most common triggers for heartburn and acid reflux. For some people, even a single cup can bring on heartburn symptoms, burning in the chest, regurgitation, or discomfort after meals.  

It might be the world’s favourite morning beverage. However, for many people, it can cause havoc on their digestive system in part due to the high caffeine levels. 

That’s because coffee naturally relaxes the lower oesophageal sphincter (LOS) — the valve that keeps stomach acid where it belongs — making it easier for acid to travel back up the food pipe. It can also stimulate acid production in the stomach, compounding the problem. 

Does Coffee Trigger Heartburn? 

In short, yes. 

But it’s not anything specific to coffee — it’s the high caffeine levels. Caffeine is a stimulant for the brain, responsible for increasing alertness and reducing fatigue. However, in the stomach, it relaxes the LOS, which acts as a valve preventing the backflow of acid from the stomach into the oesophagus.  

In a 2019 study of women drinking different beverages, coffee intake was linked to gastro-oesophageal reflux disease (GERD) — the name for persistent acid reflux.  

How Coffee Causes Heartburn 

Coffee is one of the most caffeinated beverages most people drink. Just a regular 8-ounce serving of black coffee can contain 96 mg of caffeine, which is comparable to four cups of green tea and is higher than the average energy drink (80 mg).  

These high caffeine levels are primarily responsible for heartburn and other acid reflux symptoms. But it’s not the only culprit in coffee that triggers heartburn. 

Other natural compounds in coffee also play a role, such as: 

• Acids (chlorogenic acid and quinic acid): Coffee is acidic, and these compounds can irritate the stomach lining and contribute to acid reflux. 

• Catechols: Naturally occurring compounds that stimulate the stomach to produce more acid. 

• N-methylpyridinium (NMP): Formed during roasting, this compound can actually increase acid production in some people. 

• Oils (like cafestol and kahweol): Present in unfiltered coffee (e.g. French press, espresso), they may contribute to gastrointestinal irritation. 

• Other stimulants (like theobromine and theophylline): These can also relax the LOS, making reflux more likely. 

One thing to watch for is the roast. The darker the roast, the less caffeine content. That’s why light roasts are sometimes labelled as “breakfast coffee.” Moreover, lighter roasts are more acidic, but they do have lower levels of catechols. Overall, lighter roasts are more acid-inducing — though problems with darker roasts still happen as the differences are fairly minimal. 

Does Tea Also Affect Heartburn? 

Tea also contains caffeine, so it can increase the levels of heartburn and GERD. However, the actual concentration of caffeine in tea depends on the type of tea and time steeped. Black tea and longer steeping times lead to higher amounts of caffeine, while herbal teas containing little to no caffeine. 

Not sure which tea to go for? Well, here’s a quick overview of their caffeine concentrations (per 8-ounce serving): 

• Black tea: 64-112 mg 

• Oolong tea: 29-53mg 

• White tea: 32-37 mg 

• Green tea: 24-39 mg 

Herbal teas (e.g. ginger, camomile, rooibos) are considered caffeine-free. However, spearmint and peppermint teas, while considered caffeine-free herbal teas, can still exacerbate heartburn in some people. 

What Types of Coffee Are the Worst for Heartburn? 

Not all coffee is created equally. The same variety in taste also applies to its effects on your health. Coffee isn’t inherently bad, in fact it’s a major source of antioxidants and can support gut health. The key is moderation and making sensible choices. 

Certain types are more likely to bring on reflux symptoms: 

• Light roasts: Higher in acidity and slightly higher caffeine content, which can stimulate stomach acid production and LOS relaxation. 

• Unfiltered coffee (e.g. French press, espresso): Contains more oils like cafestol and kahweol that may irritate the stomach. 

• Large lattes and cappuccinos: The combination of caffeine and milk can increase acid reflux in sensitive people. 

• Drinking coffee on an empty stomach: More likely to cause irritation and discomfort. 

• Added sugar: High amounts of sugar may increase acid reflux risk, so opt for your coffee without all the sugar and syrups if possible.  

Try choosing darker roasts or cold brew as they are usually lower in acidity and may be a little lighter on the stomach. 

Does Decaf Coffee Still Cause Heartburn? 

Yes, but not to the same extent. As mentioned, it’s not just caffeine that causes heartburn. The presence of the oils and acids in coffee, including decaf, can still irritate the stomach.  

However, overall, decaf is a much milder option, especially among people who still want a morning coffee without the burn. 

Tips for Drinking Coffee Without Heartburn 

You don’t have to give up your morning coffee. With a few sensible tips, you can enjoy a cup of coffee while minimising your risk of heartburn. 

Try these tips: 

• Choose dark roasts or cold brew for lower acidity. 

• Opt for filtered coffee instead of French press or espresso. 

• Limit yourself to one small cup per day. 

• Avoid drinking coffee on an empty stomach. 

• Give decaf a try. 

Get Tested If You Have Persistent Heartburn 

Coffee isn’t the only cause of heartburn. Nor is it normal to get severe heartburn from a single cup. Often, there’s an underlying condition that’s gone undiagnosed here. 

The Functional Gut Clinic offers a range of tests to confirm acid reflux and identify the cause. We’re experts in the diagnosis and treatment of gastro-related conditions. Get in touch today to take the first step towards relief.