7 Common Coffee Mistakes at Home (And How to Fix Them)

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You know that day when you buy a good bag of coffee, make a cup… and it’s just “meh”. Not terrible, not great. Just disappointing. Most of the time it isn’t the beans. It’s a few small mistakes in the way we brew at home – habits everyone picks up over the years.

I’ve made every one of these mistakes myself at some point, so this guide is as much a reminder for me as it is for you.

This guide is here to fix that. No lecture, no coffee snobbery. Just seven common mistakes and simple ways to fix them, so your next bag actually tastes the way it should.

1. Using coffee that’s too old

Coffee doesn’t go “off” like milk, but it definitely goes tired. After roasting, beans slowly lose aroma and sweetness. If the bag has been open for weeks, don’t expect fireworks in the cup – even if it was fantastic on day one.

How to fix it

  • Try to buy what you’ll drink in 2–4 weeks, not for the next six months.
  • Keep one bag open, the rest closed. Don’t rotate between five different bags at once.
  • If your coffee starts tasting flat and hollow, it’s probably age, not your machine.

2. Guessing the amount of coffee

One day you use one scoop, the next day “a bit more”, and you hope for the best. Result: every cup is different – sometimes weak, sometimes harsh and bitter.

How to fix it

  • Get a small kitchen scale. It’s the single best investment for better coffee at home.
  • For most methods, a good starting point is around 1:15–1:17 – 1 g of coffee to 15–17 g of water.
  • Once you have a starting recipe, you can adjust taste by 1–2 grams instead of starting from zero every morning.

If you want a simple starting point for each method, our brew ratio guide gives you ready-made recipes, not just theory.

3. Using the wrong grind size

Even the best beans will taste wrong if the grind is off.

  • Too fine: coffee is harsh, bitter, heavy, sometimes almost burnt.
  • Too coarse: coffee is watery, sour, “empty”, like brown water instead of coffee.

How to fix it

  • Think in textures, not grinder numbers:
    • Espresso: like powdered sugar or fine flour.
    • Pour-over: between sea salt and fine sand.
    • French press: like coarse sea salt or breadcrumbs.
  • When the cup is sour and thin → grind a bit finer.
  • When the cup is bitter and heavy → grind a bit coarser.

For more detail by method, our grind size guide walks you through textures and typical mistakes step by step.

4. Water that’s too hot (or straight from the tap)

Two things matter: temperature and quality. Boiling water straight from the kettle can pull out bitterness and a “burnt” edge. Very hard or heavily chlorinated tap water will also ruin flavour, no matter how good the beans are.

How to fix it

  • After the kettle boils, open the lid and give it 30–40 seconds before you pour – that usually puts you in the 90–95°C sweet spot for most brewing methods.
  • If your tap water is very hard, try filtered water or bottled water with medium mineral content.
  • If your coffee suddenly tastes better with bottled water, that’s your answer.

5. Storing coffee in the wrong place

The classic mistakes:

  • An open bag sitting next to the hob.
  • Coffee in the fridge “to keep it fresh”.
  • Beans poured into a clear jar standing in the sun on the counter.

Coffee doesn’t like light, heat, air or moisture.

How to fix it

  • Keep the beans in the original bag with the one way valve – that bag is designed for coffee.
  • After each use, gently press out the air and close the bag properly (clip if needed).
  • Store it in a dark cupboard, away from the oven and hob.
  • Skip the fridge – coffee works like a sponge for smells and moisture. Nobody wants an espresso that hints of last night’s stew.

6. Changing too many things at once

The coffee tastes wrong, so you change everything: beans, grinder setting, dose, temperature, even the brewing method. In the end, you don’t know what helped or why it’s suddenly worse.

How to fix it

  • Change one thing at a time.
  • Start with grind size or dose, not by buying a new machine.
  • Make quick notes: “+2 g coffee today”, “slightly finer grind today”. After 3–4 days you’ll know exactly what makes the biggest difference.

7. Ignoring your own taste

A quiet mistake: trying to drink coffee the way some barista on YouTube drinks it, instead of the way you actually enjoy it. If you love milk drinks, there’s no point forcing yourself into super-bright, acidic espresso “because it’s more serious”. If you love chocolatey coffees, you don’t need to pretend a very floral, tea-like coffee is your favourite.

How to fix it

  • Start with the question: “What do I want this coffee to do in my day?” Calm weekend mug? Quick weekday boost? Evening ritual?
  • Match the profile to that:
    • Comfort, chocolate, nuts → Brazil, blends, “comfort” coffees.
    • More fruit, higher acidity → Guatemala, Ethiopia, lighter single origins.
  • If you want to see how origin changes the cup, our Brazil vs Guatemala guide shows it side by side on two real coffees.

Everyday takeaway

If you only remember three things from this guide:

  1. Fresh beans + good storage – without that, everything else is a struggle.
  2. A scale and a repeatable recipe – no more random scoops.
  3. One change at a time – so you actually learn what improves your cup.

The rest is just small adjustments and finding the profile that fits your mornings.

Recommended coffees to try next

If you want to test different profiles at home, start with these three:

Brazil Fazenda Pinhal 250g
Calm, chocolatey comfort. Smooth chocolate and hazelnut, perfect for flat whites and cappuccinos.

Guatemala Antigua 250g
Sweet clarity in the cup. Blackberries, chocolate and a clean finish – great for V60 and filter brews.

Classico Blend 250g
If you’re not ready to choose sides yet, this blend sits comfortably between Brazil’s chocolatey comfort and Guatemala’s liveliness.