I hate to say it, but it is likely that your krups grinder is contributing to the bitterness in the coffee by producing a large amount of \"fines,\" or very small particles of coffee that become over-extracted in your brew process. The more uniform the grind, as achieved by higher quality burr grinders, the greater clarity and better taste you will achieve from your french press. The french press method is sensitive to grind quality, just like espresso or other methods.
Also, you probably want to use more coffee in your French Press (haven't used the Aeropress myself to comment, but Colin can). Try nearly TWICE as much coffee. At least 3 scoops as a minimum for your 12oz brew, and more likely 3 1/2. Using too little coffee will result in over-extracted and bitter results in the cup. Once you solve your main problem, you can adjust according to taste.
Your steep time sounds good. Experiment to find where you like your coffee best. If you are getting bitter results, even when using more coffee, try grinding coarser and/or steeping for a shorter time. Also consider using a slightly lower water temperature, for example waiting 15-20 seconds off of a low boil.
I think you hit the nail right on the head. Although the beans did seem to be one problem (I got some fresher ones, and make a drinkable cup with the AP), the grinder seems to be the issue for the FP.
I tried a shop-ground bag of coffee from Starbucks, and although it wasn't the freshest in the world, the result was at least drinkable, without a hint of the bitterness. Just visually comparing the result of the coarsest grind from my Krups with the stuff ground in the shop, it is obvious that the stuff I am grinding is far finer.
Guess I need to find a better grinder!
Thanks for the help, guys...you definitely know your stuff. I would never have thought to question the grinder.
Thanks for the update and sorry for the bad news. To throw out another 'rule of thumb,' I usually suggest the following for any non-trivial coffee appliance:
\"If it's being sold in a department store, it unfortunately just won't fit the bill.\"
The reality is that you are probably looking at close to a couple hundred dollars before you start seeing better burr grinders. In this camp, you will find grinders like the Solis Maestro, Baratza Virtuoso (though the early model I tried and use every day doesn't fare well on the coarse end of the spectrum; Colin since tested the latest redesign), refurbished higher-quality grinders, and at one time the Cunill Tranquillo at the bargain price of USD$200.
It used to be that you could get a Zassenhaus hand grinder for less money that did an amazing job, but their quality has since been questioned and they are more difficult to find. Note that many other models of hand-grinder will not be suitable (poor consistency).
FYI -- beware the Gaggia MM grinder, which isn't really any better than your Krups. The Gaggia MDF has a good burr set, but the build quality is not as good as the Rancilio Rocky (otherwise virtually the same burrs, I believe).
You can see an example of several burr sets at
Ken Wilson's page
, including the cheap \"bean crushers\" fake burrs employed on grinders like the Krups KMM30, Gaggia MM, and likely your GVX.
I've gone for the Starbucks Barrista grinder. I'm not ready to pay the megabucks just yet, so this one at least seems to produce usable results - it's just a little messy, is all, as detailed on the page you linked to. If this develops into a more serious hobby and I'm still grinding in six months or so, maybe I'll upgrade to something better at that time.
But for now, I'm happy. I can at least produce a drinkable cup, and just need to experiment to get the best results.
Next step is to get a roaster. The main reason for this is because it's so hard to get freshly roasted stuff in the UK, and I have to buy in fairly large quantities. At least if I buy them green, I don't have to worry about them going stale so much.
So...just need to wait a few weeks to soften up the wife before I broach the subject!