An aeropress makes a really good cup of coffee. It does take some practice though. There are a few things you can do to fix the sourness. Sourness is usually th

An aeropress makes a really good cup of coffee. It does take some practice though. There are a few things you can do to fix the sourness. Sourness is usually the outcome of low temperature and under-extraction. I suspect in your case it may be more of the latter. 1. Invest in a food thermometer - if you don't already have one. I personally like brewing around 197F - 200F range. To find your sweet spot try it at 207F and work your way down. There is a way around this (see point 3). 2. Check the grind size. If you are buying store bought coffee that is pre-ground the grain size may be too large. the Aeropress can handle much finer grinds, not quite an espresso grind, but close. The reason this is important, is if the grind size is larger the water may not penetrate all the way and or have more heat loss than advisable. 3. Pre-infusion - Soak/wet one part ground coffee to two parts water (or enough to just about cover) for 30-45 seconds in the aeropress(see point 4) or in a separate pitcher, before you add additional water. The pitcher works well, but adds to cleaning effort. 4. If you haven't tried it already. Try the inverted technique. It's a true game changer. Here's a video to get started https://www.youtube.com/watch?v=Ugj5OONvGZQ https://www.youtube.com/watch?v=Ugj5OONvGZQ