East London Coffee Company / Barista  / The Science of Proper Coffee Extraction
Coffee Extraction

The Science of Proper Coffee Extraction

When it comes to coffee – cheap can certainly be nasty! Not only when it comes to the quality of the beans, but as importantly, a “bargain-basement” coffee machine will not be as efficient at extracting flavour as a good quality machine. What is coffee without flavour, after all?

The strength, and therefore the flavour, of your coffee is determined by the dissolvable solids (TDS – Total Dissolved Solids) that are extracted from the ground beans.

This makes a lot of sense surely? I’m no scientist, and I get this. If you or your machine is unable to extract the right percentage of ‘dissolvable bean,’ your coffee will be watery, weak, tasteless and insipid. A well-extracted coffee, on the other hand, will be full of flavour. There are three things that affect this:

– An under-developed roast

– A sub-optimal grind process

– Poor brewing

On this page, we focus on the brewing and extraction part of the process – you’ve found some awesome coffee beans and really want to get the most flavour as possible.

What causes watery and tasteless coffee

As far as the roast goes, leave that to us. We take great care in roasting every single bean under the watchful eye of our experienced roaster. We leave nothing to chance and do not use mass, computer-controlled roasting methods. Each bean has different characteristics and needs to be roasted with care!

When it comes to grinding, there are two issues (i) freshly ground is best; ground coffee loses flavour very quickly (ii) grind to the correct size for your brewing method, e.g., very fine for espresso or pressurised methods and a little courser/sand like for filter or pour over systems and lastly (iii) how are you going to prepare your brew. Let’s take as an example a cheap bean-2-cup machine bought at a mass outlet. They are chasing a ‘price’ rather than a quality product, and these generally have a poor extraction percentage. The more you pay, the better the grinding burrs and the more pressure the machine generates. This is measured in bars; if the machine you’re looking at doesn’t get at at least 12 and preferably 15 bar, walk away and go and buy instant coffee while you save up for a good machine that will last you for many years.