Learning how to make coffee properly

Making coffee properly involves a lot more than putting some beans into a machine and steaming milk. Even something as simple as a flat white relies on a lot of variables, including the grind size, dose, extraction and how the milk is prepared. Small changes to any of these can have a noticeable impact on the final taste. The equipment obviously plays a part, but knowing how to control each of these variables is what actually makes the difference.

Starting with espresso

Espresso is the base of most of the coffees you'd order at a cafe. It starts with coffee beans being ground and placed into a portafilter. The grounds are then distributed and tamped to create an even bed of coffee before the portafilter is locked into the machine. Once extraction starts, the machine forces hot water through the coffee under pressure, with the liquid that comes out being the espresso.

Getting this extraction right is important because you're trying to extract the right amount of flavour from the coffee. If water passes through too quickly, the espresso can be under-extracted and taste sour or weak. If it takes too long, it can become over-extracted and taste bitter or harsh. There are several variables that affect this, but one of the most important is the grind.

Getting the grind right

Grind size determines how easily water can travel through the coffee. A finer grind creates more resistance and generally causes the espresso to extract more slowly, while a coarser grind allows the water to pass through faster. This means changing the grind even slightly can have a pretty noticeable effect on the final espresso.

This is why baristas need to dial in the grinder rather than leaving it on the same setting all the time. The goal is to adjust the grind until the espresso is extracting properly and tastes balanced. The beans, dose and other variables still matter, but grind size is one of the main controls available for changing how the extraction behaves.

Learning to steam milk

For milk based coffees, getting the espresso right is only half of the process. Steaming milk isn't simply about heating it up. The steam wand is also used to introduce air into the milk, creating the microfoam that gives drinks like flat whites their smooth texture.

The position of the steam wand makes a big difference. You need to keep the tip close to the surface to introduce air, and position it correctly to create a swirling motion that'll mix everything together. Temperature also matters because overheating the milk can negatively affect the taste and texture. The end result should be glossy milk with very small bubbles rather than a layer of thick foam sitting on top.

Putting it all together

For a flat white (my choice right now), the espresso is extracted first and the steamed milk is then poured into it. The milk should have enough microfoam to give it a smooth texture without creating the much thicker layer of foam you'd expect from something like a cappuccino. The way the milk is poured also helps combine it properly with the espresso rather than simply adding milk on top.

A good espresso can still be let down by poorly steamed milk, while perfectly textured milk isn't going to fix a bad extraction. Both parts need to work together, which is why even a relatively simple coffee can require quite a bit of technique to make properly.

My take

Making a good coffee isn't particularly complicated when each part is looked at individually. The difficulty comes from controlling all of these variables consistently. Grind size affects extraction, extraction affects the flavour of the espresso, and milk temperature and texture can completely change the finished drink.

Good beans and equipment obviously help, but an expensive coffee machine isn't gonna make you good coffee. Understanding how each part of the process affects the next is much more important. Once the grind, extraction and milk are all working together, even something as simple as a flat white has quite a lot going on behind it.