I just produced yet another perfect latte, and had to share it with this crowd. Oh man, it's just perfect!
1 - The grind (and tamp). The grinder is a Solis Maestro Plus that I've tweaked to within an inch of it's life. The grind isn't as perfect as it could be, but doubling the grinder cost for a marginal increase in consistency (like up to a Mazzer Mini, for example) just didn't seem worth it to me. The tamp is controlled by a scale. I just tamp the coffee onto a bathroom scale that sits on the kitchen counter. 30lbs every time yields a 25 second pull, every time.
2 - The brew. The Gaggia Espresso comes with one tiny 100ml boiler. The difficulty is that when you fire off the pump, it pressurizes the boiler with room temperature water from the fill reservoir. That's bad -- the boiler is so small that it cannot maintain the 95C temperature for more than a few seconds into the shot. Pre-mods, I was losing nearly 15C over the course of a 25sec pull. So I added a preheater -- it's a second boiler pulled from an old broken-down machine I got off eBay, plumbed in sequentially between the fill reservoir and the main boiler.
The other brew problem was the thermoswitch. It would cycle the heaters based on temperature -- on at 90C, off at 100C, give or take. That means that you could start pulling a shot at 90C -- which is abyssmally cold, and yields pretty nasty espresso. Alternately, you could pull boiling water through the beans, which results in scalded coffee -- no better! So I added digital controllers (Omega PID controllers, actually) to both boilers in order to maintain proper temperature. Now, I'm maintaining temp inside 1C for the entire pull.
The espresso produced is uniformly dark, produces neat little swirling "monkey-tail" streams during the pull, and I get the full "Guinness" effect for a minute or two afterwards, as the crema settles. The consistency is kind of thick and syrupy, and the flavor is ... well, it tastes just about like the coffee beans smelt, unground. Wow.
3 - The frothing. 2-hole EPNW tip, angled for maximum turbulent flow. I manufactured a brass pipe to run through a throttle valve from the boiler. The piping has to be preheated before I froth actual milk, or else the thermal mass of the big pipe will condense the steam on it's way to the milk, resulting in a watery latte. Eew, nasty. If I do preheat it, though, I get very nice dry steam, and the tip gets excellent turbulence in a 16oz frothing pitcher.
The milk comes out as an almost syrupy. It's thick enough to scoop on a spoon, if you scoop quick, but not thick enough to stand on it's own. It has the flavor of toasted marshmallow.
Ah, I just had to share that with someone. Thanks for listening.
Dan