I'm a (very) long time empeg user and lurker on this site, but couldn't resist responding to your post. I might be one of those U.S. coffee snobs, so you might want to overlook my post. I roast my coffee each week using an RK Drums roaster, and use a Cimbali grinder and JR machine daily. It took me quite a while to arrive at my preferred roast and brewing.

For a drip machine, you might want to determine you have an adequate brewing temperature of 92-96 Celcius (around 200F,) otherwise, your coffee will be bitter. The amount of brewing time also makes a big difference (can be altered with grind.) If your machine is taking more that 5-6 minutes to brew for a drip maker, it's likely taking too long. Check how others are using your machine (e.g., coffeegeek.)

Coffee, grind, water temperature are key to good tasting coffee (and roast & freshness.)