Coffee is one of the most popular drinks on the planet, which means it's surrounded by a lot of "common knowledge" that turns out to be wrong. As we've been learning about coffee for Olivenhain Coffee Roasters, we've been surprised by how many things we (and our parents) believed about coffee that simply aren't true.
Myth #1: Dark Roast Has More Caffeine
This is probably the most common coffee myth. Many people assume that because dark roast tastes stronger and more intense, it must have more caffeine. Actually, the opposite is closer to the truth — though the difference is small. Caffeine is relatively stable during roasting, but dark-roasted beans are larger (they expand more) and weigh less (they lose more moisture). So if you measure by scoops, a scoop of dark roast will have slightly less caffeine than a scoop of light roast. If you measure by weight, they're nearly identical.
Myth #2: Espresso Is a Type of Bean or Roast
Espresso is a brewing method, not a type of coffee bean or roast level. Any coffee can be brewed as espresso — it just refers to forcing hot water through finely-ground coffee at high pressure. That said, certain roast profiles work better for espresso than others (medium-dark roasts tend to produce more balanced shots), which is why you see "espresso roast" on many bags. But there's no rule that says you can't pull a light-roast single origin as espresso.
Myth #3: Coffee Beans Are Beans
They're actually seeds! Coffee "beans" are the seeds found inside the fruit of the coffee plant (called a coffee cherry). They look a bit like beans, which is how they got the name, but botanically they're seeds. True beans are legumes — coffee is not.
Myth #4: Coffee Should Be Stored in the Freezer
This one is debated, but for everyday use, the freezer is not the best place for your coffee. Every time you take the bag out and open it, the temperature change causes condensation, which introduces moisture to the beans — and moisture is coffee's enemy. The best storage method is a sealed, opaque container at room temperature, away from light and heat. If you must freeze coffee (say, to store a large quantity long-term), freeze it in vacuum-sealed portions that you only thaw once.
Myth #5: Coffee Dehydrates You
While caffeine does have a mild diuretic effect, the amount of water in a cup of coffee more than makes up for it. Studies have shown that moderate coffee consumption contributes to your daily fluid intake, not against it. You're not dehydrating yourself by drinking coffee — you're mostly drinking water that happens to be flavored with dissolved coffee compounds.
Myth #6: Boiling Water Is Best for Brewing
Pouring boiling water (212°F / 100°C) directly onto coffee grounds can over-extract the coffee, pulling out bitter, harsh flavors. Most brewing experts recommend water between 195–205°F (90–96°C) — just below boiling. If you don't have a thermometer, let your kettle sit for about 30–45 seconds after boiling before you pour.
Myth #7: "100% Arabica" Means It's Good Coffee
Arabica and Robusta are the two main commercial species of coffee. Arabica generally produces better-tasting coffee than Robusta, so "100% Arabica" sounds premium. But Arabica is a huge category — it includes both exceptional specialty coffees and bland, low-quality commercial coffees. "100% Arabica" on a label tells you what species it is, but it says nothing about quality, origin, freshness, or how well it was roasted. It's a floor, not a ceiling.
Myth #8: Fresh-Roasted Coffee Should Be Brewed Immediately
This one surprised us! Freshly roasted coffee actually needs to "rest" or "degas" for a period after roasting — typically 3 to 7 days for drip/pour-over coffee and up to 10-14 days for espresso. Right after roasting, the beans are releasing a lot of carbon dioxide, which can make the coffee taste sharp and underdeveloped. Giving the beans a few days to rest allows the flavors to stabilize and the CO₂ to dissipate. This is one of the things Graham has the hardest time being patient about.
"Wait, so we roast it and then just… leave it there? For a WEEK? That doesn't make any sense." — Graham, age 6
We'll keep busting myths as we learn more. If there's a coffee question you've always wondered about, let us know — we'll research it and report back.