Amsterdam-based Frans Goddijn is one of specialty coffee’s mad scientists. Most recently, he’s shared with us his camera work capturing transparent portafilters to monitor puck behavior during extraction. Now Goddijn gives us his latest FrankenCoffee project: A decked out moka pot that he says results in a sweet espresso-like brew, including a touch of crema.
“With a moka pot?” you ask.
“Yes,” we say, “with a moka pot.”
“How is that possible?” you ask.
First, Goddijn took his inspiration from fellow mad scientist, Hungarian Gábor Laczkó, who recently told Daily Coffee News that the moka pot is an undervalued tool in the specialty coffee world. Check out Laczkó’s “Back to the Moka Pot” video here.
For his custom moka, Goddijn chose a classic Brikka by Bialetti, in part because of its non-magnetism (more on that in a second). “It is a little cheaper, but what’s more important, it has a little pressure valve on the spout in the upper chamber that creates extra pressure in the coffee puck during extraction, and even a little crema on the espresso,” says Goddijn.
Rather than gas burner or a beam heater, Goddijn characteristically turned to second-hand lab equipment for his heating device — in this case a vintage, German-built Retsch RühroMag MH12, which importantly has a strong magnet on its underside with a controllable rotation speed. Goddijn dropped a stir bar he refers to as a “flea” in the lower chamber, and when the device is on and the magnet is rotating, the flea stirs the water and, Goddijn suspects, heats the water more efficiently and evenly.
The non-magnetic pot material is important in this stirring process, since a magnetic pot would essentially rotate, rather than the flea rotating in the chamber. Here is the Retsch RühroMag MH12 and flea in action:
Next, Goddijn followed Laczkó’s example in connecting sensors to various parts of both pot chambers, then connecting those sensors to temperature-monitoring software. When he pressed go, here’s what happened:
The hot plate starts at room temp a little over 26ºC, then heats up the bottom half, and at about 4 minutes a temperature of 100ºC is reached. Pressure builds up and then the temperature climbs again. Around 135ºC, the pressure is high enough to overcome the pressure valve and suddenly, in a brief flow, the espresso and crema rushes into the top chamber at 70-75ºC, ready to pour and taste immediately.
If this doesn’t make you want to immediately hit ebay looking for vintage laboratory hot plates, what will? And if this is your kind of stuff, we highly suggest following Goddijn on his blog Kostverlorenvaart.