Posted by Rohan Mehta on
Brewing coffee is essentially extracting the dissolved solids from the coffee beans. This process needs hot water and ground coffee. There are two things to consider when brewing a cup of coffee - contact time and grind particle size. The two are correlated and need to be kept in mind when deciding how you prefer your cup of coffee to taste.
Extraction can be defined simply as the amount of coffee solids, either less or more - taken by hot water to create the final solution we know as the humble cup of joe. Depending on the overall and average surface area of the grind particle size, will determine how quickly or how slowly your extraction happens. And in turn deliver either a higher extraction or lower extraction, based on the given recipe. Grinding the coffee finer will increase the amount of contact between the water and the ground coffee, as the particles are smaller and more easily extracted (think instantly) when in contact with the water. Grinding the coffee coarser will have the opposite effect, but you can play the game of balance between optimum grind size and length of brew time, to facilitate a full and even extraction that promotes both sweetness and body in the cup. Making the perfect cup of coffee is entirely based on each person's interpretation of ideal strength/extraction and flavour. If the grind size is too fine or the contact time is too long it will result in a bitter and undrinkable coffee that tastes awful. Likewise if the grind size if too coarse and the brew time too short, this will taste overly sour, thin and under extracted.
If you are brewing your coffee using a french press or our channi coffee method you need coarsely ground coffee, because the contact time between the hot water and ground coffee is higher than your average filter method. An added advantage of coarsely ground coffee is the ease of straining the coffee grounds from your beverage after you are done brewing. If the grind is far too coarse or the contact time is too little, the resulting coffee will be weak and sour.
What do you do when you have coffee that is over or under extracted? You tweak the recipe. If the brewed cup of coffee is under extracted (sour, thin) you increase the brew time. If the coffee is over extracted (ashy, bitter) you decrease the brew time.
We recommend investing in a burr grinder and grinding your beans just before brewing your coffee. This ensures the most vibrant flavours and aroma in your cup of coffee. If you don’t have access to a grinder, no problem, you can order pre-ground coffee from our website. Each of the grind sizes on our website correspond with the desired brewing method. When you select ‘French Press’ as the grind size, your coffee will be ground moderately coarse - suitable for a french press or the channi coffee method. If you select the ‘Espresso’ grind size we will grind your coffee quite fine - suitable for use with high pressure and short brew time, in an espresso machine.