There is nothing more discouraging than buying good coffee and brewing a bad espresso. Here are the main reasons an espresso can go wrong and how to fix it:
1- Using coffee that is not freshly roasted or freshly ground
As soon as your coffee is roasted, it begins to age, more precisely, to oxidize. Generally, "connoisseurs" agree that a coffee is at its best between 2 and 5 days after roasting. Use fresh beans, ideally not older than 7 to 14 days, and keep them properly.
The freshly ground coffee will also be the freshest and richest in taste. The most subtle aromatic compounds in coffee deteriorate within minutes of milling; It is therefore advisable to grind only the quantity necessary for the number of cups that you will brew immediately.
2- Not purging the machine
Not purging will brew your coffee with overheated water that has stagnated in your group, which is clearly not what you want. The water in your machine will often be too hot, purge it to make sure you have the right water temperature for a perfect coffee!
3- Not using milk properly
Two mistakes are to be avoided when talking about espresso recipes with milk. First of all, we do not recommend to use low fat milk: you will get a voluminous milk, filled with bubbles, without any texture or homogeneity, in addition of making the coffee less smooth, balanced and sweet. The flavor will not be as rich as with a fatter milk. Whether it's the consistency of the foam of a cappuccino or a latte art, everything is because of the milk and, you guessed it, the talent of the barista.
4- Not tamping your coffee properly
You can never tamp your coffee grounds too much... impossible! If your coffee drips, then adjust the grind or use less coffee in your filter holder.
If you tamp unevenly, leaving the coffee puck fractured or not putting sufficient pressure, your extraction will result in poor quality espresso.
5- Not following the optimal brew ratios
The brewing ratio is at the heart of all espresso recipe. The brewing ratio is measured by weighing the amount of ground coffee in the filter holder relative to the weight of the liquid extracted in the cup. For example, if you put 20g of ground coffee in the filter holder and draw a dose of 40g espresso, you will get a 20:40 or 1:2 brew ratio.
Determining the best brewing ratio is not always easy: it may vary depending on your coffee and your preferences, but generally, dark roast coffees will be better with smaller ratios, while light roasts will be better with higher ratios.
Secondly, never overheat your milk. When steaming milk for too long, your milk may experience dehydration and oxidation reactions, so you will have a loss of nutritional value and aromatic compounds, which is not very appealing. In other words, avoid overheating!
6- Not cleaning your espresso machine
It is important to purge your group and steam tip before and after each cup of coffee. These are quick and regular cleaning procedures that can minimize dirt accumulation. We do not talk about periodic cleaning, like descaling, it is simply a quick cleaning that ensures that the machine is in the best possible condition. It is still advisable to do a complete cleaning at every 90 coffees (approximately).
7- Leaving coffee in the basket after pouring an espresso
Leaving used coffee in the filter holder is probably not the best idea: this bad habit accelerates the formation of coffee oils and grime inside the group and the filter holder, thus requiring a more frequent cleaning.