5 Mistakes You're Making With Coffee That Are Ruining Your Brew

#3 is a major buzz-kill.

We've seen great strides for making at-home brewing fun. We can now stay sufficiently caffeinated via upgraded espresso machines, new how-tos for a french press, a perfect pour-over, homemade lattes, and even the Dalgona whipped coffee trend.

Regardless of where your skills lie on the coffee-making spectrum, there are likely a few steps in the process that leave room for improvement. Here are the biggest mistakes you may be making when brewing coffee at home, plus how to fix them.

Not matching the grind size to your brew style

Different styles of brewing require different grind sizes. This is because the extraction rate of coffee grounds is higher when they're more finely ground (thanks to the larger surface area that's exposed to the hot water). Using more finely-ground beans also increases the amount of time it takes water to pass through the coffee grounds—think of it as a more "crowded" filter basket—which ups the amount of time that the water and grounds are in contact.

All of this translates to this rule of thumb: Brew methods with a shorter contact time require more finely ground coffee beans; those with a longer contact time are best with coarser grounds. If you're making espresso, Turkish coffee, or Aeropress, use finely-ground beans. Use a medium grind for pour-overs, stovetop espressos, single-cup coffee makers, and drip coffee. Finally, use coarse grounds for French press or cold brew. And when grinding, be sure to use a burr grinder or have the shop grind it for you.

Using tap water

It's easy to forget that coffee is approximately 98 percent water. "Nailing the proper water chemistry will dramatically change your home coffee quality," says Justin Lacher, Wholesale Educator for Chicago-based craft coffee company Intelligentsia. "Tap water quality is pretty much never right, and bottled water can be too soft. Using filtered water from a Brita or fridge dispenser is ideal. When in doubt, you can use Third Wave Water. It's super easy to order online and use at home—you just add a packet to distilled water to create the perfect solution for coffee."

Brewing at the wrong water temperature

Water temperature is incredibly important. When brewing, it should be between 195 F and 205 F—not lukewarm, not boiling. Using a thermometer (or a water kettle with one that's built-in) is the easiest way to make sure your water is sufficiently hot, but if you don't have either options on hand, you can bring water to a boil and let it stand for around 30 seconds before you brew.

Not measuring your coffee

"People often add too much coffee to make a stronger brew, but if you use too much you run the risk of getting sour flavors," explains Lacher. Additionally, despite what you may think, more coffee will not make a stronger—or better—cup of coffee. Past a certain point, you're just wasting good beans when you keep adding extra coffee grounds because you'll over-extract them and end up with an undrinkable cup. This is due to the way that coffee (and therefore caffeine) is extracted when your ground beans and water interact, similar to the reason the grind size matters above.

There's only so much caffeine you can extract from your beans before you ruin the flavor, due to the contact time, extraction rate, and water to coffee ratio. If you want stronger coffee, rather than adding extra grounds, buy a lighter roast—darker roasts are actually weaker, caffeine-wise, than light roasted beans.

Additionally, always weigh or measure your grounds. "I recommend a simple and inexpensive kitchen scale to weigh coffee in grams. Just add in 16 to 18 times as much water and you're good to go." If you don't have a scale, you can measure 2 tablespoons of coffee per 6-ounces of water.

Brewing coffee that's expired

Old coffee won't make you sick, but coffee past its expiration date does deteriorate, right alongside its taste and aroma. Check the roast date on the packaging of your beans. If it's more than two to three weeks old, your coffee will likely have already begun losing flavor and freshness. Whole beans last longest (they stay fresh for up to a month), while ground coffee is best within two weeks of opening.

In addition to using fresh coffee beans, remember not to grind them until you're ready to brew. The easiest way to make sure you're always using fresh beans? Sign up for a coffee subscription service—we love Grounds and Hounds' Coffee Club—that lets you select your style of beans, brew method, and frequency of delivery before shipping directly to your doorstep.

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