Saturday, April 28, 2012

Pulling Coffee

I like shiny

I like learning weird little skills. The past year has been pretty good for that. I've dabbled in joinery, learned the basics of how to clean and oil a watch, and now I'm learning to pull an espresso. Don't get me wrong, I still love moka, but I like espresso too and have been curious about learning to make it for a long time.

Since I enjoy the process of doing things as much as the result and often more so, I chose the most basic espresso machine of them all. For about a week now, I'm the proud owner of an Europiccola, a manual piston lever machine by La Pavoni. The design hasn't changed much since it was first introduced in 1961. Perhaps the most significant change is the introduction of a pressurestat that maintains water temperature and pressure in the boiler with less fuss than the pressure valve and double power switch of the older models. It's quite refreshing to encounter a household appliance these days that assumes you're a responsible adult. There are all kinds of ways you can burn or scald yourself or spray steam and coffee grounds all over your kitchen with it, if you don't follow the instructions.

You make espresso by forcing about 90-degree water through a densely packed puck of finely-ground coffee at a high pressure, between 8 and 10 bar or so. In a manual piston machine, your arm, amplified by a lever, produces the pressure. If everything goes well, you squeeze out a rich, thick, creamy coffee emulsion that starts dark brown and fades gradually to a pale tan, and collapses into an oily, aromatic, strong but not bitter, very dark espresso topped by a thick, long-lasting crema.

The production of a cup of espresso is a function of a whole bunch of variables. The temperature of the gruppo—the pump and screen assembly where the portafilter screws in—and the portafilter itself determine the temperature of the water when it hits the puck. The quantity of coffee, the fineness of the grind, and the tightness of the tamp determine the resistance to flow, which determines the pressure as a function of the time it takes to push the dose of water through. Another important factor is the pre-infusion—wetting the puck before the actual pull. The only things the machine holds relatively constant are the temperature of the water when it leaves the boiler and the quantity of water in a single pull.

So brewing a cup of espresso from a given little heap of beans becomes an optimization function between seven variables (quantity of coffee, grind, tamp, water temperature at the filter, length of pre-infusion, water quantity, force on the lever), out of which only four (coffee quantity, grind, pre-infusion, and water quantity) can be relatively easily controlled accurately on the La Pavoni. Tamp, force, and water temperature at the filter are very touchy-feely.

They say it takes months or even years to "bond" with a La Pavoni. I can believe that. However, at this point I can also say that it's not nearly as intimidating as it's sometimes made out to be. I have no experience with making espresso manually, and while I did throw away a few shots of espresso on the first day I played with it, I can already fairly confidently produce something that's at least as good and usually better than what I'd get if I ordered an espresso at a halfway-decent café in my neck of the woods.

I'm a long way from getting the process truly under control, though. The quality of my shots varies a lot. I've managed to produce a couple that were really promising, much better than regular café quality; on the other hand, the one I just pulled yesterday morning looked great—rich, brown crema and all that commotion—but tasted somewhat bitter and lacking in aroma, no better than the ordinary café stuff really. I have a hunch the problem was with the water temperature—I let the machine sit around for longer than usual, but forgot to screw in the portafilter while it was heating; then to heat the portafilter I ran some water through it, which may have overheated the gruppo, or still left the portafilter too cold. Or perhaps I just screwed up some other way.

In any case, the three shots I pulled yesterday afternoon turned out better.

I like the La Pavoni for similar reasons I like the Fuji X-Pro1. It puts a minimum of layers between you and the process. It's really satisfying to operate. It does exactly what you tell it to do, and doesn't attempt to out-guess you or fix your mistakes. It has a lot of clever little design touches, but they're intended to help you do things right, rather than to mitigate the things you do wrong. For example, the portafilter screws in such a way that the spouts are nearly parallel to the handle. This makes it feel unstable when tamping the coffee. However, it's only unstable if your tamping is unsteady. After a bit of practice, my tamping has improved a quite a bit, and if I'm actually tamping directly down, like I'm supposed to, the handle stays rock steady. If it wobbles, it's telling me that my tamping is off. If the spouts were more perpendicular to the handle, it would feel stabler, but you'd have a harder time telling if your tamping is off, and you'd be much more likely to develop bad habits.

The upshot is that if you don't like the result, you know it's something you did, and can then change it to make it better. There's special kind of freedom to that. Brewing coffee or taking a photo becomes a little ritual, a fixed sequence of actions performed fluidly; the better you get at it, the better it feels, and the better the end result.

I just read in today's paper that the Finnish champion barista just opened a coffee bar next door. That's a lucky break. I think I'll drop by for a gold standard reference shot, and see if he's the kind of guy I can ask for advice if I get stuck taming my La Pavoni.

1 comment:

  1. Hi Petteri,
    I am going to open a cafe' next month. And against all advice i'm going to use a lever operated machine in my cafe'. I wish i could find a La Pavoni in India. Anyway i've decided to buy an Astoria. Thanks for sharing your experiences. This is one of the best pieces i've read recently about pulling coffee. Apart from visiting the new Barista bar, will you also be trying any books as a reference to hone your coffee making skills? If yes, then please share the details.

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