One difference between your local craft-coffee shop and the corporate competitors, is the quality of the espresso. There are some simple steps to pulling an espresso. Here is a simple introduction to getting that great shot.
So, how do you make great espresso?
1. Start with great coffee that's at least a 5-6 days off-roast. The coffee flavor will settle and balance by that time because it's had a chance to de-gas some c02.
2. Grind about 19-21 grams at a very fine setting. The grind size and volume will have a lot to do with how long your shot takes to pull and that affects flavor, big time.
3. Level the coffee in your portafilter. We use a tool to make sure the coffee is perfectly level and evenly distributed in the basket.
4. Tamp the coffee bed in the portafilter. A solid, straight down tamp is best. Don't twist or spin that tamp while you're applying pressure. You've already distributed, all you need to do is evenly compact the coffee. You can give it a spin without pressure
5. Lock the portafilter into the group head and start your shot. A traditional double shot is usually a little less than two ounces.
A great espresso can take anywhere from 25-35 seconds to extract. You're emulsifying oils and sugars because of the high-pressure environment. You should see a slow stream of coffee coming from the portafilter with rich browns and reds, then as the extraction finishes the color will blond significantly. That blonding is ok and will help give your espresso balance, but you don't want too much of it (maybe 1/3 of your total extraction should be blond at most).
*There are a few methods to pulling a ristretto, which is a shorter shot with less volume. The simplest is to up-dose your coffee volume a couple of grams, then pull your shot to one ounce. It should still extract in about 20+ seconds. A ristretto going to be a strong and vibrant espresso. Our fellow coffee geeks may take some umbrage with us over-simplifying a ristretto - forgive us lol.