Maximising the flavour from coffee beans starts with making sure that the extraction is optimised. Extraction is the process that occurs when water and ground coffee come into contact. In science speak, this is the dissolving/dissolution process and the dissolved flavours are what produce the end result in your cup; the rest of the undissolved solids are what make up the coffee grounds.
If we toss the coffee beans into the water, as they are, there’s not much for the water to dissolve, due to the robustness of the coffee bean. All that would be extracted is the outer layer. Hence the need to grind, or open up the coffee bean, increasing its surface area and allowing the water to pass through it and maximise its flavour collection. A roasted coffee bean is around 30% water-soluble. This means that you can extract about this much of the coffee bean’s mass in water. The rest is cellulose and other plant based stuff which forms the structure and integrity of the bean.
Crushing the coffee beans into a fine grind and dumping it in hot water until it dissolves is not enough to make great tasting coffee. The only thing this will achieve is extreme bitterness as the dissolving/dissolution process will be inconsistent as the crushed coffee will be in different sizes. Unfortunately, not all the flavours coffee possess are nice so we must control the amounts of flavour we extract by measuring, weighing and timing the brewing time, this is achieved by ensuring a uniform and consistent grind profile by adjusting and setting the coffee grinder correctly.
Extraction is a balancing process. Ideally, we want to avoid under or over extracted coffee; the best results sit somewhere in the middle. Under extracted coffee is when the water has not had a chance to penetrate the coffee fully while over extracted coffee occurs when the water has over penetrated the coffee and the balance of flavour is upset.
The key identifiers of an under extracted coffee are in its taste in terms of sourness, a lack of sweetness and somewhat salty aftermath. because we haven’t extracted the coffee flavours for long enough. The overall finish of an under extracted coffee is bland with no lingering aftertaste experience.
Over-extraction occurs when you take too much of the soluble flavours out of the coffee. This level of extraction results in unfavourable flavours coming through which unbalances the coffee and leaves a rough and bitter aftertaste.
The correct extraction is where the coffee is balanced, sweet and the flavours are identifiable with a lingering finish that remains after the coffee is consumed. If you are unsure whether you are getting the best extraction from your coffee, please let us know and we’ll get it right for you.