The most common coffee brewing mistakes

Your daily morning cup of coffee is probably the most important part of your day. It's a shame, though, that homemade brews rarely taste as good as those prepared by a barista at your favorite cafe. This is due to small details that can completely change the taste of the drink.

All this brewing fun, professionally called Coffee Brewing, is simply based on physics and chemistry. If you want to drink excellent coffee, especially top-quality Specialty Coffee beans, you need to control every step. I'll show you how to master parameters such as extraction to bring out the true charm of the beans.

Once you eliminate basic mistakes, your daily brew will reach a whole new level. If you're looking for solid foundations, check out our guide for beginner baristas. Now, let's look at what most often stands in our way to the ideal taste.

Why is it so easy to make mistakes when brewing coffee at home?

We usually stumble due to a lack of precision and treating the laws of physics or chemistry carelessly.

We often think that good coffee only needs boiling water and whatever we have on hand. This is a mistake, because then a bitter or unpleasantly sour liquid ends up in the cup. Only when you understand the extraction mechanism will you take full control of the process in your own kitchen.

Every small detail – from the cleanliness of the dripper to the hardness of the water – affects the final taste. Even the most expensive Specialty Coffee beans will lose their charm if you treat them carelessly. It's better to learn a few simple rules and get into the habit of good brewing.

Is incorrect water temperature a common mistake?

It is the temperature that determines how quickly and which specific compounds you extract from the bean.

Pouring boiling water over coffee is probably the biggest sin we commit at home. The official guidelines of the Specialty Coffee Association (SCA) clearly state: the best temperature is between 89°C and 96°C. Experts from this organization for the Specialty Coffee segment narrow this range even further: to 92–96°C.

If you overdo it and the water exceeds 96°C, you will reach so-called over-extraction. Boiling water simply destroys delicate aromas and releases an unpleasant bitterness. Your coffee will become flat and lose its unique character.

On the other hand, water that is too cold (below 90°C) will also spoil the effect. You will then get under-extraction, meaning the water will not have time to dissolve the best parts of the beans. The brew will be bland, watery, and unpleasantly sour.

You can find more details about the standards directly on the Specialty Coffee Association website. Buy a kettle with a thermometer, and you'll see how much it changes your morning.

How does random grinding ruin the taste?

How coarsely you grind the beans determines the contact time of the coffee with water and its flow rate.

Each piece of equipment requires a different particle size, also known as Coffee Grind Size. Too fine a grind will block the water, causing it to drip too slowly. The result? Burnt, bitter coffee and an astringent aftertaste that will linger with you for a long time.

Too coarse particles, on the other hand, will cause the water to flow through them like a sieve. The coffee will not have time to release its oils, so the brew will be watery, flat, and tart.

Another trap is cheap blade grinders, which, instead of grinding, simply cut the beans into uneven pieces. Such dust and large fragments brew at completely different rates, making the brew taste simply chaotic. The solution is a good burr grinder – check out our recommendations in the burr grinder ranking.

Here's how to choose the grind size for a specific brewing method:

• Espresso requires a very fine grind, resembling flour or fine sand.
• Moka pot and AeroPress prefer a fine-medium grind.
• Pour-over methods, such as the V60 dripper, prefer a medium grind size similar to table salt crystals.
• Chemex needs a medium-coarse grind for water to flow freely through the paper filter.
• French press and cold brew are best treated with a very coarse grind resembling sea salt.

How do incorrect water-to-coffee ratios ruin the whole effect?

The strength of the brew and how clearly you perceive individual flavor notes depend on the ratio.

Eyeballing your coffee measurements guarantees that you'll drink something completely different every day – and rarely something good. Baristas call this the Brewing Ratio. Invest in a kitchen scale accurate to 0.1 gram, and you'll take control of the process.

For pour-over methods, start with a ratio between 1:15 and 1:18. This means for every gram of coffee, you pour 15 to 18 grams of water. If you prefer a strong, rich brew, aim for around 1:15, while a milder taste will be achieved with a ratio of 1:17 or 1:18.

For espresso, these numbers are different because the brew is highly concentrated. The Italian institute Istituto Nazionale Espresso Italiano (INEI) has defined traditional parameters that can be easily applied in your kitchen. Check out the following summary for home devices:

• Espresso: ratio from 1:2 to 1:2.5 (INEI's own standard is about 7g of coffee for 25ml of brew).
• AeroPress: ratio from 1:14 to 1:16 (e.g., 15g of coffee for 210–240g of water).
• Drip V60 and Chemex: from 1:16 to 1:17 (i.e., 30g of coffee for 480–510g of water).
• French press: ratio from 1:15 to 1:16 (e.g., 30g of coffee for 450–480g of water).
• Traditional coffee brewed in a mug: from 1:15 to 1:18 (e.g., 10g of coffee for 150–180g of water).

Where to store coffee to preserve its taste?

The way you store coffee determines its freshness, as poor conditions quickly destroy delicate aromatic oils.

It's often rumored that the best place for a bag of beans is the refrigerator. This is a mistake, because humidity and constant temperature changes are very harmful to the delicate structure of coffee. When you take out a cold package, water immediately condenses on the beans, which destroys the aroma and promotes mold.

Proper storage, also known as Coffee Storage, involves protecting coffee from four enemies: air, moisture, light, and heat. Oxygen causes the fats in the beans to become rancid, and the brew tastes flat. Sunlight, in turn, accelerates the aging of the beans.

Instead of the refrigerator, pour the beans into an airtight, dark container with a one-way valve. Place it in a dry cupboard, away from the oven or radiator. Your favorite coffee will retain its full flavor for several weeks after opening the package.

How does dirty equipment spoil the taste of the brew?

Cleaning your espresso machine will save you from the bitter taste of old, rancid oils.

Dirty equipment is a silent killer of good taste, which we often forget about. During brewing in an espresso machine, moka pot, or dripper, mineral deposits and oily residues are left behind. These residues burn with each subsequent use, giving a stale, metallic aftertaste.

Lack of cleaning will also affect the device itself. Limescale clogs pipes, reduces pressure, and impairs water flow. What's more, moisture in milk tubes is an ideal breeding ground for bacteria and mold.

Develop a habit of daily rinsing and regular descaling of your equipment. Clean devices are essential, without which even the best specialty beans will not show their richness.

How to quickly improve your daily brewing?

You'll achieve a better taste with a few simple changes to your daily habits.

Brewing coffee is great fun, where small things make a big difference. When you start controlling water temperature, grind size, proportions, and ensure clean equipment, your home brews will rival those from cafes. Every small adjustment will affect the balance of sweetness, bitterness, and acidity in your cup.

Experiment and introduce these small changes step by step. Let us know in the comments which mistake most often occurred in your kitchen. Also, subscribe to our newsletter to regularly receive practical tips and proven recipes.