[Blak Smyth]

I reread your OP and see you did play with different roast levels, it may actually be that you just do not like that bean that you selected. You will find some winners and some losers in the process. If you can break down what flavors you taste it will help us try and narrow down a cause. I would try and roast a different bean, try some other preroasted beans and compare them to a different brew process. This should really answer a lot of questions.