Why Does Coffee Have Caffeine?
Coffee has caffeine because the coffee plant makes it to protect itself. Caffeine is a natural pesticide. It tastes bitter and is toxic to many insects, so it helps keep bugs off the plant's leaves and cherries. It even slows down other plants trying to grow nearby. The caffeine buzz we enjoy is a side effect of the plant's defense system.
At Tapestry, we roast every coffee to order at our roastery in St. Paul, Minnesota. If you want the full buzz, our Loom Blend is the coffee we brew every day in our Lakeville cafés. If you want the flavor without it, try our Decaf Colombia.
Why Does the Coffee Plant Make Caffeine?
Caffeine is found throughout the coffee plant: in the leaves, the cherries and the seeds we roast into coffee beans. Scientists have found it does a few different jobs for the plant.
1. It keeps bugs away
Caffeine is bitter, and in high enough amounts it can disrupt or even kill insects that try to eat the plant. A plant full of caffeine is a lot less appealing to a hungry beetle.
2. It keeps other plants from crowding in
When coffee leaves and cherries fall, caffeine seeps into the soil around the plant. That makes it harder for competing seedlings to sprout, so the coffee plant has more room, water and nutrients for itself.
3. It brings the bees back
Coffee flowers put small amounts of caffeine in their nectar. Researchers have found that this low dose helps honeybees remember those flowers and return to them, which means more pollination. The plant uses a big dose of caffeine to keep pests away and a small one to keep pollinators coming back.
Coffee isn't the only plant that figured this out. Tea and cacao make caffeine too, and they evolved the ability on their own, separately from coffee. That's how useful caffeine is to a plant.
Arabica vs. Robusta: Why Some Coffee Has More Caffeine
The two main coffee species carry very different amounts of caffeine:
- Arabica has about 1.2% to 1.5% caffeine. It grows at higher elevations, where there are fewer pests, so it doesn't need as much protection.
- Robusta has about 2.2% to 2.7% caffeine, nearly double. It grows lower and hotter, where pests are more of a problem.
That extra caffeine is one reason robusta tastes harsher and more bitter. Every coffee we roast is arabica, picked for flavor first.
Does roast level change caffeine? Not much. Caffeine holds up well during roasting, so a light roast and a dark roast have about the same caffeine by weight. If you measure with a scoop, light roast comes out slightly ahead because the beans are denser. Either way, the difference is small. How you brew matters a lot more.
How Much Caffeine Is in Your Cup?
An 8 oz cup of brewed coffee has about 95 mg of caffeine on average. The real number depends on the coffee, the grind, how much coffee you use and how you brew it.
| Drink | Typical size | Approx. caffeine |
|---|---|---|
| Espresso | 1 oz single shot | about 63 mg |
| Drip or pour over | 8 oz | about 95 mg |
| Cold brew | 12 oz | 150 to 240 mg |
| Decaf | 8 oz | about 2 to 5 mg |
These are general estimates, not lab tests of our coffees. For French press, AeroPress and more, see our full caffeine breakdown by brew method.
How Caffeine Affects You
Throughout the day, your brain builds up a chemical called adenosine, which makes you feel tired. Caffeine has a similar shape, so it fits into the same receptors in your brain and blocks adenosine from doing its job. You don't feel the sleepiness until the caffeine wears off.
Most people feel caffeine within 15 to 45 minutes, and it takes about 4 to 6 hours for your body to clear half of it. That's why an afternoon coffee can still keep you up at night. The FDA says up to 400 mg a day, about four 8 oz cups, is generally fine for most healthy adults. If you drink coffee every day and suddenly stop, headaches and tiredness for a few days are common.
What About Decaf?
Decaf starts as regular coffee. Before roasting, the green beans go through a process that removes at least 97% of the caffeine. A cup of decaf still has a few milligrams, but not enough for most people to notice.
Good decaf should taste like good coffee. Our Decaf Colombia has notes of dried cherry, brown sugar and clove. We brew it in our cafés for anyone who wants an evening cup.
Find Your Coffee
Whether you want a strong morning cup or a mellow decaf, it starts with fresh coffee. Every bag we sell is roasted to order in St. Paul and shipped in 1 to 3 business days. Not sure where to start? Take our 60-second coffee quiz and we'll match you with a coffee that fits how you brew.
