A quick primer on fresh-ground coffee: Most people are amazed to learn that once a coffee bean has been ground, it starts to lose flavor immediately.  Ground coffee loses its best flavor attributes after 24 hours, whether you freeze, seal it, or vacuum-pack it, regardless of what commercial package coffee labels tell you about "shelf-life".  After seven days, all the best flavor attributes are gone and your coffee will no longer be crisp, nuanced and sweet. This is why all good restaurants, coffee houses, and coffee bars have a grinder in the premises and grind their coffee just before brewing it.

Fresh-ground and fresh-brewed is the best way to enjoy coffee.  If you must keep ground coffee for a long time (over seven days), seal it air-tight (Ziploc® bags are good) and put it in the freezer. It will be like frozen meat. Acceptable, maybe even good, but not as good as never-frozen steak. You are better off storing whole (not ground) roasted coffee beans. Whatever you do, do not put it into the refrigerator. The worst enemy of ground coffee is air (actually oxygen) and humidity. The refrigerator is the most humid place in the house! Besides coffee will acquire all the flavors around it (like garlic, onions, etc).  If you want to keep ground coffee for a few days, keep it in an air-tight canister in a cool, dry place. Most kitchen cupboards fit this description quite well. Keep all coffee away from heat and light.

There isn't a sadder sight to our eyes than to see a coffee lover buying roasted whole coffee beans in bulk (3 to 5 lbs) and then grinding the whole bag at the store! Unless s/he is having a party and is going to drink all that coffee in the next 24 hours, it is just a shame! Now you know why that just-ground coffee tastes so good!

So what kind of coffee grinder should I use?  At home there are three grinders you can use: a) a commercial grinder (like Bunn® or Grindmaster®). These are the best for consistency and durability, but they are bulky (not really designed for a household kitchen) and expensive!  But for quality, they cannot be beat. You can pick a clean, lots-of-life left-in-it, used one for a few hundred dollars. That would be our first choice.  b) a household burr grinder, and c) a household blade grinder.

If you are serious about your coffee quality and either roast at home or buy whole bean (in our opinion, buying whole bean is the only way to buy roasted coffee), then you need a powerful (over 100 watts) burr or blade coffee grinder. Using a coffee grinder at home produces significantly and noticeably better-tasting coffee than buying ground coffee at the store (or online!). A burr grinder is good for all types of coffee brewing methods. A blade grinder is not good for very fine coffee grinds like espresso and Turkish/Greek coffee.  A powerful blade grinder is fine for French Press, Pourover, Drip or Vacuum coffee makers. Because burr grinders give you more control over the grind, they are the preferred choice and, of course, cost more.  So, unless you make espresso and need very fine grinds, you do not need a "conical burr grinder".

What is the difference between a burr and blade grinder? A burr grinder has teeth that cut the coffee beans in one pass, without overheating, nor destroying them. A burr grinder has different settings and allows you to pick the type of grind (very fine to coarse) desired. This is what commercial coffee grinders do. A blade grinder has a rotating knife that cuts the bean repeatedly (until pulverized, if kept on long enough or if you have a weak motor). Weak grinders (under 100 watts) heat the coffee beans causing flavor loss. On a blade grinder the degree of grind is controlled by the amount of time the engine is engaged. So, if you are going to get any grinder, make sure it has a powerful motor. 

If you want control, get a burr grinder. If you are not picky, a powerful (it cannot be overemphasized!) blade grinder is all you need.