Světlá vs. tmavá praženka: Která má více kofeinu? Vyvracíme běžné mýty

If you've ever stood in the coffee aisle wondering whether to grab a light roast or a dark roast, you've probably heard conflicting advice about caffeine content. Some say dark roast is stronger and packs more caffeine; others insist light roast is the real energy booster. The truth is more nuanced—and often surprising. In this article, we'll separate fact from fiction, explore the science behind caffeine retention during roasting, and help you choose the best roast for your morning cup.

At Hills Bros., we roast everything from light to dark, and we know that flavor preference and caffeine expectations go hand in hand. Whether you're brewing a pot of Original Mild - Light Roast - Ground or reaching for a bold dark roast, understanding what's really in your cup can transform your coffee experience. Let's dive into the myths and facts.

The Caffeine Myth: Why So Many People Get It Wrong

The most persistent myth in coffee culture is that dark roast contains more caffeine than light roast. This belief likely stems from the bold, intense flavor of dark roasts—they taste 'stronger,' so people assume they deliver a bigger caffeine kick. In reality, caffeine content is remarkably stable throughout the roasting process. A single coffee bean loses very little caffeine as it roasts; instead, it loses water weight and expands in size.

Because dark roast beans are roasted longer, they become less dense and lighter in weight. If you measure your coffee by volume—using a scoop—you'll actually get fewer dark roast beans per scoop compared to light roast beans. That means a scoop of light roast can contain slightly more caffeine than the same scoop of dark roast. The difference is small, but it flips the common assumption on its head.

• Tip: For the most accurate caffeine comparison, measure your coffee by weight (grams) rather than volume (scoops).

Light Roast: Bright, Acidic, and Packed with Potential

Light roast coffee is roasted for the shortest time, typically just until the first crack. The beans retain more of their original moisture and density, which means they are heavier per bean. This density is why light roast often yields a slightly higher caffeine concentration per scoop. Flavor-wise, light roasts are known for their bright acidity, fruity notes, and complex floral aromas—qualities that can get lost in darker roasts.

For many coffee drinkers, light roast is the go-to choice for morning energy without bitterness. Our Original Mild - Light Roast - Ground is a perfect example: it delivers a smooth, mellow cup with a gentle caffeine lift that feels clean and crisp. If you enjoy tasting the origin characteristics of the bean, light roast is your best friend.

• Quick fact: Light roast beans are denser, so a standard 2-tablespoon scoop contains more individual beans than the same scoop of dark roast.

Dark Roast: Bold Flavor, Less Density, Same Caffeine

Dark roast beans are roasted until the second crack or beyond, resulting in an oily surface, deep brown color, and smoky, chocolatey flavors. The longer roasting time drives off more moisture, making the beans lighter and more porous. Because of this, a scoop of dark roast contains fewer beans by weight—and therefore slightly less caffeine—than a scoop of light roast. However, the difference is minimal: usually less than 10%.

What dark roast lacks in caffeine density, it makes up for in body and richness. Many people prefer dark roast for its low acidity and bold, roasted taste. If you're looking for a robust cup that pairs well with milk or cream, dark roast is an excellent choice. Our Donut Shop - Medium Roast - Ground - Premium Arabica sits in the middle of the spectrum, offering a balanced profile that appeals to both light and dark roast fans.

• Did you know? Dark roast beans are more brittle and easier to grind, which can affect extraction time in espresso machines.

The Role of Brewing Method: How Preparation Affects Caffeine Extraction

The roast level isn't the only factor that determines caffeine in your cup. Your brewing method—drip, French press, espresso, or pour-over—plays a huge role. For example, espresso uses a fine grind and high pressure to extract caffeine quickly, but the serving size is small. A typical 8-ounce drip coffee actually contains more total caffeine than a single shot of espresso, regardless of roast level.

Water temperature and brew time also matter. Hotter water and longer contact times extract more caffeine. So if you're using a French press with a dark roast and steeping for four minutes, you might get a higher caffeine yield than a quick pour-over with a light roast. The key is to match your roast to your preferred brewing method for the best balance of flavor and energy.

• Pro tip: For maximum caffeine extraction, use water just off the boil (195–205°F) and brew for at least 3–4 minutes.

Other Coffee Myths: Acidity, Bitterness, and 'Strong' Coffee

Beyond caffeine, several other myths surround roast levels. One is that dark roast is more acidic—in fact, light roast has higher acidity because the roasting process breaks down chlorogenic acids. Another myth is that 'strong' coffee always means high caffeine. In everyday language, 'strong' often refers to flavor intensity, not caffeine content. A dark roast can taste strong but deliver the same caffeine as a milder light roast.

Bitterness is another misunderstood attribute. Dark roast is not inherently bitter; poor roasting or over-extraction causes bitterness. A well-roasted dark bean can be smooth and sweet. Similarly, light roast is not always sour—when brewed correctly, it can be vibrant and balanced. The best way to find your preference is to try different roasts side by side.

• Myth buster: 'Extra bold' labels on coffee bags usually refer to roast level or flavor intensity, not higher caffeine content.

How to Choose the Right Roast for Your Morning Routine

Now that you know the facts, how do you pick? If your priority is maximum caffeine per scoop, light roast is your best bet. If you crave a rich, low-acid cup with chocolatey notes, go dark. For most people, the difference in caffeine is negligible, so flavor should be your main guide. Consider your brewing method: light roasts shine in pour-over and drip, while dark roasts excel in espresso and French press.

Hills Bros. offers a wide range of roasts to suit every palate. Our 100% Colombian - Medium Roast - Whole Bean - Premium Arabica is a versatile option that bridges light and dark, with a smooth body and bright finish. And if you're in the mood for something indulgent, our English Toffee - Instant Cappuccino Mix provides a sweet, caffeine-friendly treat without the fuss of brewing.

• Try this: Buy one light roast and one dark roast, brew them side by side, and see which one you enjoy more—your taste buds know best.

The next time someone tells you dark roast has more caffeine, you'll know the real story: caffeine content is nearly identical between roasts, and any difference comes down to bean density and how you measure your coffee. The best roast is the one that makes you smile with every sip. Ready to explore? Start your morning with a cup of our 100% Colombian - Medium Roast - Whole Bean - Premium Arabica and taste the difference quality makes.