12 Popular Myths About Coffee Busted (Backed by Science)

Ah, coffee… That delicious drink enjoyed around the world. One of my favorite things to do when traveling, in fact, is to taste that part of the world’s coffee. And it’s amazing how different it can be but also how much everyone seems to love it!  We know it wakes us up and the smell starts the day off right. But, almost accidentally, we’ve also associated coffee with a bunch of myths which may or may not be true. Let’s look at these 12:

It dehydrates you [MYTH] – All studies done on coffee show that it does NOT, in fact, dehydrate you. The average cup of coffee is about 98.7% water. While coffee does not replace the need for water in your daily diet, saying it causes dehydration is a misconception. The fact that coffee does act as a diuretic probably contributed to this myth at some point. But causing you to go to the bathroom and dehydrating you are very different things.

It sobers you up [MYTH] – Not only is this myth untrue, it’s dangerous. The idea that having a cup of coffee after drinking will help you sober up is completely false. If anyone ever suggests they are fine to drive home after some coffee, do not listen to them! Where this likely comes from is the energy boost from the caffeine, making one feel awake and aware when in fact they are not. The amount of alcohol in a person’s system remains the same, and any alcohol-induced impairment does NOT change from a cup of coffee.

It stunts your growth [MYTH] – While no one is advocating that coffee be added to a child’s daily diet, no studies have been able to prove that coffee stunts growth in any way. The closest scientifically backed data is that it mildly reduces calcium absorption in the body.

Mildly meaning that 1 tablespoon of milk will offset 8 ounces of coffee. Hardly reason for concern, it seems. There really is no reason to have a child drink coffee, but don’t freak out if it happens. Still, this myth lives on.

Espresso has more caffeine than regular coffee [MYTH] – This is an apple to oranges myth. While equal parts of espresso to coffee would show espresso as being more caffeinated, that’s not how people drink them. Espresso is typically drank in 1-2 ounce servings. An ounce of espresso has about 30-50 mg of caffeine while the same amount of coffee has about 8-15 mg. But coffee servings are usually around 8-24 ounces. This easily makes 1 serving of coffee much more caffeinated then 1 serving of espresso.


It will affect your sleep [FACT] – Coffee certainly has the ability to disrupt sleep. This only occurs when you drink it within 6 hours of going to bed, though. Additionally, coffee reaches it’s peak strength within an hour and it takes only 5 hours or less for half of it to be eliminated from your body.

All in all, this means that an afternoon cup of coffee is not going to affect your sleep. Coffee, likely many things, is healthy in moderation. If you drink too much of it, or drink it in the middle of the night then, yes, your sleep will be affected.  But that is more a result of the person habits and how they are using the beverage, as opposed to coffee being ‘bad for sleep’.

It’s addictive [MYTH] – This myth has some merits, but overall it is not true. While a regular coffee drinker who stops drinking can experience some pretty bad headaches in the short term, scientists say this doesn’t qualify as an addiction. Also, coffee drinkers who quit do not exhibit the same, dangerous drug seeking behaviors that other addicts do. Quitting coffee is not going to require you to go through severe withdrawal periods or going to a rehab center to ‘get clean’. On top of that, addictive drugs have been proven to have negative long term effects, while coffee has shown to have health benefits.

Coffee is bad for pregnant women [MYTH] – This myth likely came from the ‘better safe then sorry’ mindset. The fact is, not much is known for sure about the effects of caffeine on the fetus. Studies have found nothing to indicate there iss significant risk. With that said, doctors recommend moderation in the amount of one 12 oz cup of coffee per day, max.

You must use boiling water to brew coffee [MYTH] – There is logic in boiling water for coffee, as it purifies the water and cold water will result in flat coffee because it won’t extract it well (unless you cold brew and let it sit over night). But once it boils, you want to let it sit for a minute before you pour it over the coffee. Basically, you want water just under boiling. Water that’s too hot will sacrifice taste and quality.

The dark roast has more caffeine than light roast [MYTH] – The opposite is true in this case. Dark roasts are roasted longer which causes them to lose some mass. So, per scoop, light roasts are denser and therefore will contain more caffeine. Dark roasts have that strong, rich flavor that people love but it doesn’t relate to more caffeine.

Keeping coffee in the freezer preserves it [MYTH] – The best way to keep coffee fresh is to store it away from light and moisture. Keeping it in the pantry in an airtight container will do the trick. You also want to keep it away from heat, so if you’re house is very warm, you can use the fridge.

The problem with the freezer is that every time you take it out and put it back, the change in temperature causes moisture, which is not good for the coffee. If you’re stocking up and don’t plan on using it for a good month or so, the freezer would be ok in this case.

It helps with weight loss [MYTH] – There are no scientific studies that support the idea that caffeine helps with weight loss. Drinking coffee does give a short-term boost in energy, and many athletes do drink coffee (or caffeine in another form) prior to exercise for a boost in energy. But this is a short-term effect and, as tolerance develops, decreases significantly. Nothing long term, like weight loss, has been proven.

All coffee has the same amount of caffeine – Coffees vary greatly. They are brewed differently, the beans are different and therefore can have significant differences in the amount of caffeine you’re getting. One good example – McDonald’s has 9.1 mg of caffeine per fl oz while Starbucks coffee averages about 20 mg per fluid ounce.

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