Coffee quantity -
Grind size* -
Water temp -
Add the coffee to the brewer and place it on scales. Pour all the water in one go and start the timer.
Wait until the timer hits 4 minutes, then pick the brewer up and give it a gentle swirl to break the crust and cause the coffee to drop to the bottom.
Wait another 2 minutes so all the fines can settle on the bottom, place the plunger on top of the brewer and without plunging slowly decant into a cup.
Sometimes a brew just doesn't work out. Sometimes it's bitter, like chewing on bark, and sometimes it'll be like sucking on lemons. So how do you *fix* your brew?
Overly sour coffee is a sign your coffee is underextracted, that is you haven't extracted all the good stuff out of your coffee.
Overly bitter coffee is a sign your coffee is overextracted, meaning you've extracted too much from your coffee.
The variables that can influence extraction are: grind-size, coffee-to-water ratio, time, and temperature.
The smaller the particles of coffee, the more you'll be able to extract and the quicker you'll be able to do it. So finer coffee has a lot more surface area, allowing the coffee to extract much quicker, but that just makes it easier to overextract the coffee. Grind-size will often be the easiest variable to adjust to fix a coffee.
The coffee-to-water ratio is the amount of coffee you have in relation to water. Mostly, this will affect how strong your coffee tastes, but can also affect extraction with higher coffee-to-water ratios increasing extraction.
The longer you brew a coffee, the more you'll extract. This is a great measure to help you with other adjustments - if a recipe says 3 minutes and your brew takes 5 and tastes overextracted, then you can tweak other variables to decrease the time and get your extraction under control.
The hotter your coffee is, the more you extract... in simple terms, anyway. Different compounds in coffee will extract more easily at different temperatures, but for the most part if your water is too cool your coffee may be underextracted and if it is too hot it can be overextracted. The ideal range can vary depending on the coffee, brew method, and time, but generally you wouldn't go over 97C or much below 92C.