Offering to make the after dinner coffees on your espresso machine is only natural. It's not much fun if it takes you 20 minutes or so to produce half a dozen cappuccinos, though, so the first one is stone cold and flat as a tack by the time the last one is made. Below is a guide to producing 6 excellent coffees in less than 6 minutes.
Start by turning on and priming your machine before dinner. Stack your cups on top to warm up and lock your portafilter into the group.
6 cappuccinos will need 500ml (about a pint) of milk, so you'll need a 1.5 litre jug for frothing, like the one on the right. (A$29.00.)
To speed things up, grind enough coffee for 6 shots (about 50g) before dinner and store in an airtight container.
You're Off! Fill the double basket, strike & tamp, lock and brew 30ml per cup. Knock out the portafilter, wipe with a bit of kitchen paper, repeat and repeat. This should take about 2 minutes for the 6.
As soon as you've finished the last shot, open the steam valve for a couple of seconds and let a few ml of water out. The "headspace" gives you extra steam.
Turn on the "Steam" switch and pour 500ml of ice-cold milk into your 1.5l jug. Wait till the "Heating" light goes out, submerge the tip of the wand in the milk and open the valve right up.
Your milk will just about triple in volume as it's frothed. When you have enough froth submerge the wand a bit and hold the base of the jug with your free hand. When it's too hot to touch, it's ready. Close your steam valve.
Fill your cups (these are 200ml, probably a bit big for cappuccino) and serve. Elapsed time from starting to fill the portafilter was 5 minutes and 38 seconds. Don't forget to clean the steam wand, turn OFF the steam switch and refill the boiler.
Note that one of the reasons I recommend a machine with a 300ml brass boiler as a "minimum" is that smaller boilers just don't have enough steam to froth 500ml.
On a slightly different subject, one of the things I get asked fairly often is how to produce a "Cafe Crema". This is basically a long coffee (about 150 - 180ml) produced as a continuous espresso shot. The important thing to note is that the shot TIME should be 25-28 seconds, and that I recommend using 14g of coffee (a double).
Note that the "water debit" on most espresso machines is probably around 200 - 250ml in 25 seconds. This means that the grind of the coffee needs to be very carefully adjusted to JUST above the fineness needed for 100ml in 25 seconds; a single "click" on most grinders is usually enough. You are actually trying to slow the flow down just enough for decent extraction. If you get the grind right the results are pretty good, see the photos below.
18 seconds after pressing the "brew" button.
About 180 ml after 26 seconds, and it didn't taste too bad at all.
The machine used in the photos above was a Quaha Napoletana, and the coffee was Espresso Meridionale (100% Arabica.)