What do you like for breakfast?

For some, it’s a quick bowl of cereal. For the health-conscious, it might be Greek yogurt and berries, or maybe some flaxseed waffles. Traditionalists will make bacon and eggs, or a stack of pancakes. Those in a rush might grab an Egg McMuffin on their way to work or school.

No matter the breakfast, though, it will almost always be accompanied by either coffee or tea.

It’s a good idea to start the day with a caffeinated beverage – with the obvious exceptions of sodas or energy drinks, which are loaded with sugar, carbs and calories. Caffeine will not only wake you up and increase your alertness; it can also improve your brain function, elevate your mood and even boost your performance if you hit the gym before work.

(Pro tip: have that cup of coffee after you eat. Research shows that black coffee before breakfast can wreak havoc with blood glucose levels.)

But what if you’re a tea person instead of a coffee person? Will tea provide the same benefits?

Short answer: Sort of.

Slightly longer answer: Yes, but you’d need to drink more tea than coffee – because the two beverages contain different amounts of caffeine.

Caffeine occurs naturally in about five dozen plants, most of which are native to the Southern Hemisphere or East Asia. The plants create the substance in order to deter pests and herbivores, to attract honey bees, and to stop germination in neighboring plants.

The best-known sources of caffeine are the fruit or leaves of just a few plants:

• Coffee beans from the coffee plant
• Tea leaves from the Camellia sinensis plant (often known as the tea plant), used to brew black tea, white tea and green tea
• Cocoa beans from the cacao plant

Caffeine is also present in kola nuts (once used to make Coca-Cola and Pepsi, now chewed for medicinal purposes in some cultures), guarana (often added to energy drinks) – and yaupon holly, yerba mate and guayusa, the only types of herbal tea that contains caffeine.

“What about caffeinated beverages like soda?” we hear you ask. You’re right. There is caffeine in most soft drinks, primarily the brown ones. At one time, caffeine was extracted from coffee beans and added to soda; these days, manufacturers add synthetic caffeine that’s been produced in factories (most of them in China). The same goes for energy drinks, although as we’ve mentioned, some add guarana (or guayusa) for an added caffeine boost.

The good news: synthetic and natural caffeine are chemically identical. The not-so-good news: there are very few regulations governing synthetic caffeine, and few inspections of the facilities that make it.

So tea and coffee naturally contain caffeine. But the amount of caffeine in a cup of black tea or a cup of matcha, a cup of coffee or an espresso shot, can vary widely.

Two factors are responsible for the amount of caffeine in a cup of coffee: the type of coffee beans used and the way the beans are brewed.

Caffeine and Coffee Beans

Let’s start with the two main types of beans, Arabica and robusta. Generally speaking, unroasted green Arabica beans have about half the caffeine content of robusta beans. The amount of caffeine in different varietals does vary, but only slightly.

Why is there such a difference? Robusta plants are able to grow in more hostile environments than Arabica plants because they’re better able to fight off threats to their survival. Some of the biggest threats are inspects and pests – and since caffeine is an effective insect repellent, it’s believed robusta plants evolved to contain higher caffeine levels, in order to protect themselves.

Varietals matter, but so do growing conditions. Studies have found that the altitude at which coffee plants are grown, and even the amount of shade they get, affect their caffeine content. For example, plants grown at high altitudes contain 10% less caffeine, on average, than those grown at medium-high altitudes. And since robusta usually grows at lower altitudes where there are greater numbers of pests, it needs more caffeine to survive.

One important note: the widespread belief that lighter roasts contain more caffeine than darker beans is not literally true – because coffee beans lose mass and density the longer they are roasted. A scoop of light roast will indeed have more caffeine than a scoop of dark roast. But a pound of light roast will have less caffeine than a pound of dark roast – because of their difference in mass.

So a cup of dark roast may often be “high caffeine” compared to a cup of light roast, simply because you need more beans or grounds to brew it. 

Caffeine and Coffee Preparation

The way you make your coffee will have a major impact on how much caffeine it contains. There are three key factors:

• Grind size: A fine coffee grind provides more surface area for extraction, meaning that more caffeine will be extracted in the brew. With a coarse grind there’s more coffee “packed” into each piece, so less caffeine can be extracted.
• Brew time: The longer you brew coffee, more caffeine will be extracted. (Another common belief debunked: more pressure won’t extract more caffeine. That would take much more pressure than you can create with even an espresso machine or French press.)
• Temperature: Higher temperatures do produce more caffeine content – but not in the range used to brew coffee. Espresso, home brewing and commercial brewing machines all use approximately the same temperatures.
  What about cold brew coffee, which should theoretically contain less caffeine because it’s made with cold water? Actually, it will initially have a higher caffeine level, because it’s made with at least twice the amount of coffee grounds. But when cold brew concentrate is diluted for drinking, its caffeine content ends up being about the same as regular brewed coffee.

We do need to discuss temperature in our next section, though.