One of the many many reasons we came to love coffee is the alertness and awakeness feeling it gives us, and that comes from our beloved methylxanthine alkaloid; caffeine. Caffeine impacts the brain by acting as a central nervous system stimulant. While Health Canada recommends that healthy Canadian adults limit their caffeine intake to no more than 400 mg of caffeine per day, some studies found that 200 milligrams of caffeine is a healthy daily amount for mood enhancement and boosting cognitive performance.
But caffeine content varies drastically, since it's based on many factors that dictate how much actually ends up in the cup. Let’s go over some of those factors and give some rough estimates on milligrams of caffeine in each brew method.
Coffee species or the type of bean has a direct impact on caffeine content. On average, Robusta beans have twice as much caffeine content as Arabica beans. When it comes to roasting, roast degree also affects the caffeine in the beans. Debunking the myth that dark roast contains more caffeine, it's actually the opposite!, not for the reason many believe it to be. The other myth around the same subject is darker roasts contain less caffeine since the roasting process “burned” some of it off. Which is not true since the roasting temperatures do not impact the molecular compound, even for very dark roasts. Darker roasts have less density and weigh less than lighter roasts, so pound-for-pound you get less caffeine per unit of measure.
When it comes to brewing and coffee preparation, there are a few things that change the amount of caffeine extracted. Grind size being a main one, the finer the grind, the larger the surface area of the coffee, allowing more caffeine to be released into the drink. Brew time also impacts the caffeine extraction, the more time coffee and water sit together, the more caffeine is extracted. Although, it is believed that 90% of caffeine extraction occurs in the first minute of brewing. Water temperature has a say in this as well, typically hotter water enables more caffeine extraction in the same amount of time.
Different preparation methods tend to extract the coffee differently and produce different caffeine content. Here’s an estimate on the average amount of caffeine in a typical brew type.