I believe you will need to add more coffee and/or let it extract longer. For the short extraction time you used you will likely need finer ground coffee, but since you are working with pre-ground I would first try letting it brew a little longer, but it that tastes bitter the shorten the brew time and add more coffee. It may take you a few tries to discover what works.I just got my Aeropress today and have made a couple cups of coffee with it. I used freshly ground Starbucks Sumatra beans (no haters, I live in a small town and it was all that was available today). I used two Aeropress scoops and used water from my electric kettle. I put in a little water to let the grounds "bloom" as I have seen suggested online. I then added water to the "2", stirred for 10 seconds, then pressed. It did not take me 20-30 seconds to press as suggested by the instructions. That could be one problem. I then added about 50% more water to the concentrate. I found the cup week. My question is do you add water the the bottom, middle or top of the "2"? My numbers have circles around them. I have seen pictures of what I assume to be older models where the numbers are in more of an oval. Thanks!!