Quote from Nanook:
Now, how can a barrista consistently make the crema on my coffee? (which was my original question posted on page 4)
Thanks. (not trying to be difficult, just want to know the technique -- sometimes I get crema and sometimes not)
I'm not a shot expert, but is your water hot enough, your beans roasted recently, and just ground? I suspect part of the crema results in the right oils being present in proper amounts - and if they dry up then it won't work.
Also Espresso roasts are darker than regular, and you have to grind it pretty fine. It's more like powder than the chunky sand you use for drip. You don't want to use a drip grind in an espresso because it will be flavorless. A finer grind allows for the faster saturation required by espresso makers. Likewise, a drip is a compromise between a french press and an espresso machine. It soaks the coffee for a bit, so you want bigger chunks of coffee.
When you brew, the initial extraction tastes much better than what comes later. What comes out of the grind first is what we love about coffee. The longer the coffee soaks, the more of the bitterness is extracted. So that's the theory behind espresso - grind it pretty fine and push the water right on through very quickly. But it's a fairly complex affair.
On the other side is a press, where the coffee is soaked for several minutes. This will give you a more complex brew, but it does have the tendency to draw out more bitterness. This also explains why one uses a very coarse grind for a press - you want to keep as much of the late extraction stuff in the coffee and not in the brew.
If you use an espresso grind in a proper drip machine, it will be a bitter brew as you extract more of the "yuck" part of coffee.
Also, getting water hot enough can be a challenge for many systems, especially drip.
And if you really want something pretty cool, look up vacuum brewers. I might get one of these some day.
To reach people who are insane-nutso about coffee, check out the forums at CoffeeGeeks.com. Also, here's a good post:
http://www.boingboing.net/2005/08/09/espresso-crema-shots.html