Three Common Mistakes Hot Coffee Lovers Make and How to Properly Keep Your Coffee Warm

Many people love their coffee hot—especially freshly brewed hot coffee, because the aroma is at its most vivid at high temperatures.

Although good coffee still tastes great as it cools, many of us are in the habit of finishing a cup while it's hot. If we can't, we try to keep it warm or even reheat it. Done wrong, these habits strip the coffee of its aroma, leave it flat and lifeless, or give it a scorched, bitter edge.

Here are the most common mistakes, how they affect flavor, and how to enjoy your coffee properly instead.

Mistake 1: Using a heater plate to keep warm

At FrontStreet Coffee we've noticed that whether you leave a whole pot sitting on the machine's warming plate or use a USB-heated mug, both approaches hold the coffee in a continuously heated state. It's the same as overcooking food: the flavor distorts and the coffee becomes unpleasant to drink.

Mistake 2: The microwave

Microwaves heat by radiation rather than conduction, which causes two problems. First, while the microwave runs you can't monitor the coffee's temperature, so it's hard to judge the heating and the coffee often ends up burnt. Second, radiation heating is uneven: some portions overheat while others stay cold, and the overheated parts develop a distinctly burnt, bitter taste.

Mistake 3: Keeping coffee in an insulated French press

An insulated French press will hold its temperature, but even after you press the plunger down, the coffee keeps extracting from the grounds at the bottom. The result is over-extraction—which is exactly why, when brewing with a French press, you should pour the coffee out as soon as the brewing time is up.

The Fix: Switch to a thermos

Whether we're hosting events, giving lectures, or exhibiting at shows, FrontStreet Coffee always uses thermoses to keep coffee warm. A thermos replaces any external heat source and simply preserves the coffee's own heat. It also sidesteps the over-extraction problem of leaving coffee in a French press.

Coffee brews best at around 90°C, and freshly brewed coffee is often too hot to drink right away. In that case, pour out the portion you'll drink immediately, and transfer the rest to a thermos— a good one will keep coffee warm for hours. Whether you like your coffee scalding, warm, or merely lukewarm, just remember the three essentials of good coffee: freshly roasted, freshly ground, freshly brewed.

One more thing: FrontStreet Coffee does not recommend re-steeping spent coffee grounds. Unlike tea leaves, coffee gives up most of its aromatic compounds in the first brew; a second pass will only pull out undesirable flavors.

FrontStreet Coffee Recommendation

If you brew at home and often find yourself with more coffee than you can drink, an immersion brewer like the French press is a wonderfully easy place to start—it works just like steeping tea. FrontStreet Coffee recommends a coarse, raw-sugar grind (about setting 10.5 on an EK43s, or 26 clicks on a hand grinder), a 1:15 ratio (15g of coffee to 225g of water), water at about 90°C, and a 4-minute steep before pressing slowly.

For a fragrant, low-fuss cup, try FrontStreet Coffee's Strawberry Candy—a Geisha blend of Costa Rican honey-processed coffee and Panamanian washed Geisha. Steeped in a French press it releases rose, citrus, grape, and dried blueberry aromas, and with milk it turns into strawberry taffy. If you'd rather have a low-acid, full-bodied black coffee with rich oils, choose FrontStreet Coffee's PWN Golden Mandheling: triple hand-sorted plus machine sorting, roasted medium-dark, with deep spice, caramel, cedar, and dark chocolate notes and a syrupy, velvety mouthfeel.