My addiction to coffee is no secret. It’s borderline obsessive and soon I’ll be all “Hi I’m Jittery Joey” at CAA meetings (Coffee Addicts Anonymous). Coffee is what I look forward to when I go to bed (to the point that it keeps me awake as a psychosomatic reaction to the thought of caffeine) and it’s what I look forward to as soon as the caffeine high is over. The only objection? Stomach irritation. Like everyone else, I pointed to its acidity.
But first, we need to clarify something. When acidity is used to describe coffee it can mean both taste and chemical acidity (pH). It’s gotten so confusing coffee vendors have avoided labeling packages with acidity.
“Related both to the roast and to variety. This term is akin to the description of acidity in wine, not to acid content. Indeed, retailers may avoid using this term in order to avoid confusion, and rely on terms such as “bright” or “lively.” - http://www.thecoffeefaq.com/2coffeebeans.html#flavorterms
The chemical acidity of coffee is actually around 5.0-5.1, which is similar to carbonated water and less acidic than fruit juice.
Light Roast Is More Acidic!
One of the biggest mistakes coffee buyers make is thinking that dark roasts taste more acidic (and have more caffeine). Actually, the opposite is true: light roasts (beans that haven’t been roasted for very long) have more of the natural acidic taste of the coffee bean, and they also has more caffeine. As the beans are roasted longer, they lose acidic taste, chemical acidity, and caffeine. They also get more oily (think french roasts.)
What’s really interesting is a recent study that showed that dark roasts not only have less acidity, but also make your stomach produce less acidity (2). Based on all this, you would think that dark roasts are the solution.
Some Like It Hot (and Long)
If only it were so easy. I’ve been using a french press for quite some time, namely because I love the flavor that long extraction times at hot temperature produces. But when my stomach started going down Tear Boulevard, I pivoted from light to medium to dark roasts, even drip coffee with paper filters. Nothing was really helping. At that point I took to the airwaves and other patients told me they could tolerate espressos when they could tolerate no other form of coffee. That made wonder if maybe it’s the process and not the beans. Espresso machines don’t require different beans and like french presses, use a metal filter so they extract oils (whereas paper filters don’t let them through). The main difference: the extraction time is about 20-25 seconds instead of 4 minutes.
Updated hypothesis: coffee brewed in prolonged heat is the main cause of stomach irritation. Maybe it activates tannins? Maybe it extracts less of the acids?
Extraction Time The Problem
To test this out, I bought a $30 Aerobic Aeropress which simulates the rapid extraction time of espresso machines, except they use paper filters. The result? Pain free! I even tested a super-acidic light roast, and it went down like a champ. Taste was definitely different than the press: much smoother, less full body, but the flavor profile was still fantastic. A nice bonus was that cleaning was cake (about 10x easier than a french press), and filtering with paper also lowers diterpenes which have been associated with higher cholesterol levels (1).
Conclusion: even a super-acidic roast didn’t give me stomach issues with the rapid extraction method and paper filter.
I find this result interesting because while conventional science keeps blaming acidity of coffee as the cause of stomach issues, alternative health practitioners are going in the opposite direction, linking deficiency in stomach acid and disease and readily prescribing betaine HCL to help with digestion and gut issues. It seems unlikely that coffee, which is only slightly acidic, would cause widespread gastric issues if the pH of your stomach’s acid is 1.5-3.5.
“Since pH is a log scale, the stomach is normally 100 to 1000 times as acidic as a cup of espresso” - http://paleohacks.com/questions/11555/coffee-on-an-empty-stomach#axzz2EiX8qxDr
Bottom Line: If coffee gives you issues, put away your pH strips and try out a shorter espresso extraction method or the cold-brewing method to avoid heat-extraction altogether. If chemical acidity really is the problem (in which case carbonated water and any fruit juices should also bother you) consider trying Coffee Tamer, which claims to neutralize the acid without changing the flavor. It contains calcium carbonate and a small amount of potassium and magnesium.