I've never been much of a coffee drinker. I was one of the few weird university students who could get by without multiple cups of XL Tim Horton's per day, and the few times I needed to stay up all night to get a report done I'd drink a Pepsi for the caffeine boost. I would enjoy the occasional frozen coffee drink which though is very likely much closer to a milkshake with some coffee flavouring than to an actual cup of coffee. A lot of it had to do with the fact that when I drank coffee it seemed to make me ill - either too jittery from an excess of caffeine or worse, a full-day "coffee hangover" during which I would have no appetite and feel gross and nauseous.
However in recent years I started noticing that this coffee hangover didn't occur with all types of coffee, nor did I ever feel it with other caffeinated or acidic drinks. We've been to Hawaii a few times over the past winters and drinking fresh ground coffee purchased right from the farms didn't affect me once. We started purchasing whole bean coffee for home use that was locally/freshly roasted (currently we subscribe to Phil & Sebastian out of Calgary) and again, none of it ever affected me, but I was definitely not building a tolerance. Almost every time I would take a gamble on drinking restaurant coffee, including espresso drinks (which have never bothered me at home), I would get sick. The only common denominator in the coffees that didn't make me sick seemed to be that they were from places that advertised using fresh, recently roasted beans.
I always assumed that the coffee hangovers had something to do with caffeine and acidity and potentially brew method, but that just didn't really add up. Sure, Starbucks and Tim Horton's do have typically more caffeine than other types of coffee but if a dark roast is supposed to be lower acid and lower caffeine than a lighter roast, why were medium roasts with bold acidity from Phil & Sebastian fine to drink at home, but a dark roast cappuccino at a restaurant that didn't use fresh beans made me sick? Why did the drip coffee we made from fresh roasted beans in Hawaii not bother my stomach?
Further, once I started drinking good fresh coffee, I really developed a taste for it and generally have no problem drinking it straight black. But how do I know when it's safe to order in a restaurant or cafe?
This morning I finally sat down and spent a good hour researching what might be causing my coffee sickness, and I think I have finally found the culprit: not acidity, not caffeine levels, but RANCIDITY.
Here's a summary of what I learned:
- The longer coffee beans are roasted, the darker the roast and the more oils from inside the bean get to the surface. The oils can also naturally escape the bean, even with lighter roasts, the longer roasted beans sit on a shelf.
- The oil on the outside of the bean can go rancid EXTREMELY quickly - potentially within hours if exposed directly to oxygen, humidity, and light.
- Rancid coffee oil on the outside of the bean can cause the coffee itself to also spoil.
- Rancid coffee can cause the coffee to taste bitter and stale (if the coffee you have doesn't actually smell like coffee anymore, it's stale) and upset the stomach or cause other digestive issues (including heightening coffee's laxative effects).
After roasting, whole coffee beans should be stored in an opaque airtight container with a one way valve to allow for off-gassing at approximately 20 C and consumed within one month. After GRINDING, those ground beans should be used within a couple of hours.
Apparently, any pre-ground coffee you buy is almost always rancid or well on its way. As well, commercial grade coffee is allowed to have up to 4% defective beans (which can mean broken, moldy, beans that are actually bugs, etc.) in the mix which also contributes to bad flavour and increased rancidity. A large tub of Folgers for example is pretty much guaranteed to be rancid by the second time you use it.
Most people are able to stomach rancid coffee just fine with no digestive effects (though I'd argue that non-rancid coffee is not much of a laxative) so if that's you and you're fine with the taste, enjoy the fact that you can drink coffee anywhere you want without becoming ill for a day.
Unfortunately for me, I'm going to have to stick with coffee that I know is not rancid - freshly ground and roasted within a few months of consumption. This limits me to home, or pretentious cafes. Which is maybe not the worst thing ever because having made it to age 31 without ever developing a caffeine addiction is definitely something to be proud of.
Note: I didn't provide references because unfortunately I did all my research on my phone and then sat down to type this up, and none of my references actually had references of their own, though some of the articles were written by chemists. This could all be complete BS, or it could be truth - I choose to believe it because it makes sense scientifically and I'm 100% positive that it's not in my head. But just don't use this information for a science project or anything unless you're going to put the claims to the test in a lab!