There is nothing quite like that first cup of coffee in the morning. However, if yours tastes a little off, your coffee machine might not be the culprit. According to Michael Strickland, Head Barista and Product Training Lead at De’Longhi, small everyday mistakes can have a surprisingly big impact on flavour. From grind size to milk temperature, these common missteps could be quietly sabotaging your brew.
1. Using the Wrong Grind Size for Your Brew
Strickland explains that grind size is the gatekeeper of flavour because it controls how quickly water flows through the coffee. If your grind is too coarse, water rushes through and the result is a weak, sour, or even metallic cup. Too fine, and you will get a harsh, bitter finish. The key is balance, though finding the sweet spot often takes manual trial and error unless your machine helps automate the process.
2. Guessing Your Coffee-to-Water Ratio
If you are eyeballing your measurements, that could be your first mistake. Precision is everything, says Strickland, since the ratio directly affects the body and balance of the drink. He points out that most roasters provide a golden ratio on the bag, and many bean-to-cup coffee machines now simplify things with pre-programmed drinks menus that handle the calibration for you.
3. Brewing at the Wrong Temperature
Temperature plays a bigger role than many realise. Strickland notes that darker roasts are more porous and extract easily, so they require slightly cooler water around 90°C to 92°C to avoid bitterness. Lighter roasts are denser and need higher heat up to 96°C to 98°C to unlock their complex acidity. To avoid playing chemist every morning, he suggests choosing a machine that adjusts temperature automatically once you select your roast type.
4. Using Poor-Quality or Unfiltered Water
Since coffee is roughly 98% water, its quality matters just as much as your beans. Strickland warns that minerals like sodium, calcium, and magnesium all impact the flavour profile and final taste. Even if your tap water seems fine, using a filter helps strip out impurities and prevents limescale that can damage your machine.
5. Using Stale Coffee Beans
Freshness is non-negotiable. As coffee is exposed to air, it oxidises, losing sweetness and body and becoming flat or watery, says Strickland. While opinions vary, he notes beans are typically at their best for just one to two weeks after opening, but only if stored correctly in a vacuum using a sealed, airtight container.
6. Storing Coffee Incorrectly
That brings us to storage. The biggest mistake people make is storing coffee in the fridge or freezer, Strickland explains, where beans can absorb moisture and odours. Instead, he recommends buying smaller bags more frequently rather than buying in bulk, and ensuring beans are stored airtight at room temperature.
7. Overheating Your Milk
If your latte tastes dull rather than creamy, your milk could be too hot. Strickland says the biggest error people make is overheating milk, often steaming past 70°C because they want an extra hot coffee. Unfortunately, this loses the natural sweetness and creamy texture. For the best results, aim for between 55°C to 65°C, depending on whether you are using dairy or alternative milk.
8. Neglecting to Clean Your Machine Properly
A clean machine does not just affect taste; it affects performance too. A clean machine is essential for both good coffee and long-term performance, Strickland stresses. He advises rinsing milk systems after each use and cleaning brewing units around once a month, along with regular descaling. Otherwise, limescale dulls flavour and blocks pipes.
9. Treating Every Coffee Bean the Same
Finally, not all beans behave alike. No two beans are the same, says Strickland. A light, fruity Ethiopian roast extracts very differently to a dark, chocolatey Italian roast, requiring different grind size, temperature, and ratios to achieve the ultimate flavour profile. While baristas spend time perfecting this through trial and error, home users can lean on machines that save profiles for different beans and allow recalibration at the touch of a button.
