One of the keys for good espresso is the crema. It's a foam emulsion involving coffee oils and proteins. Once you grind coffee, the increase in surface area goes up tremendously and oxidation begins to degrade those essential ingredients. If your coffee wasn't roasted and ground fairly recently, you wont get a very good shot of espresso. I can guarantee Muse isn't getting shots like
this out of his coffee pot. You just can't get that with preground, frozen, reblended grinds.
And using a blender or blade grinder for espresso making is also a recipe for disaster in making real espresso. As pressurized water is being forced through a tightly tamped coffee puck, consistency in grind size is necessary to avoid channeling. When the majority of water follows the path of least resistance, much if the coffee is left unextracted and the result is a weak shot.
Bottom line, a good grinder is as important (if not more so) as a good espresso machine. Of course if you're using a drip or perc, it's a lot less important. Definitely go to coffee oriented sites for better info. Home-barista and coffeegeek are probably some of the better ones.
This.
But as he mentioned, it looks like he is using a Moka, and doesn't care for strong coffee.
The Moka won't make true espresso, but it does a fairly good job of impersonating it.
Personally, I use a Bodum French Press when not making espresso.
If one is using an espresso machine, the grinder is a very, very important part of the overall package. How consistent and finely-ground the result is will depend entirely on the cost of the grinder. Burr grinders, in general, are consistent, but not all can be adjusted to get the optimum grind, though optimum grind can very between machines, especially at the sub-$150 level of espresso machines.
For coffee methods that aren't espresso, the beans don't need to be as cared for. Though the result can still bring a far more tastier beverage if one does indeed grind the beans and store them properly.
Oxidation, as L00PY stated, is a big enemy. The oils have a significant impact on flavor, even in other brewing methods, but most significantly in espresso where they are critical, often the difference between "uck, where's the sugar and milk?!" and "ooo, this doubleshot is tasty!".
Again, diluting it with milk, reduces the necessity for quality brew prep, but the espresso still shines in dilution, and the absence of crucial oils
will bring down the quality of a cappuccino or latte.
Oh, and coffeegeek is an amazing site. Where I learned all my little tricks, especially the popcorn popper coffee-roasting technique.
