Saturday, November 19, 2005

The Perfect Espresso

There are some areas where art and science form a natural synergy to create a thing of true beauty. Motor racing, photography, rocket science... we're all familiar with the engineering detail and artistic flair needed to bring these fields into their full potential. But nowhere is this more true than in the act of drawing espresso into the world.

From the point of view of an engineer, espresso comes from a machine. It requires proper operation and correct maintenance. But the artist feels all these factors, operates the machine by touch and sound. While the engineer is carefully scrutinising the cup and the stream of foamy espresso to determine the instant at which the pour is complete, the artist is anticipating the flavour of the cup, the sensation of the crema, the jolt of awareness inspired by the first taste.

The making of espresso begins long before you ever see the beans. Somewhere in the world, they are grown by a farmer who picks them at the right moment and sells them to coffee roasting factories. These green beans may travel around the world, or a short distance from Papua New Guinea to Brisbane.

The best beans in the world, hands down, came from Sumatra. For those of you with short attention spans, tsunami covered the coastal areas of Sumatra twice at the beginning of this year; if you can get Sumatra beans, they're at least a year old. We wish them well rebuilding their agriculture and their beautiful island, but at the moment, the best option for single origin beans is back where it all began: Ethiopia and Africa.

Some prefer to roast their own beans; this will insure freshness, but if you have the luxury of a coffee roaster and wholesaler nearby then it's best to enjoy the expert roast done by others with a great passion for coffee and a sensitive understanding of the subtleties of the roast.

Espresso roasts are dark. Among dark roasts, flavour will depend on the beans used and the roast itself. A very dark roast of a very high quality bean will not be unpleasantly bitter, but rather will have a sort of purity to the flavour. Blended beans can further refine that flavour, giving it form and shape. As with brandy, there is no correct choice; coffee drinkers try many different beans and blends before they choose their favourite. Blended coffee has polish, but single origin beans have personality - these are brought out by the roaster/blender and you should choose the one you prefer.

When you go to the grinder with fresh beans (1 week old is considered about perfect) you will notice that the ground coffee holds together well, as if slightly moist. It comes out in bursts, rolling around into the group handle of your espresso machine. As you press it down, you will see how compressible it is - it can be necessary to tamp three times before the coffee is ready to pour.

The quality of the grind is crucial. Espresso is made by allowing the ground beans to become barely damp, and then forcing the water out of them with steam. A very fine espresso is made by allowing the surface area to become as high as possible. The limiting factor is that as the coffee becomes more powdered, it interferes with the metal filter at the bottom of the group handle and prevents the espresso from pouring. Although some pressure will produce a rich crema, too much will mean that the coffee comes out in little drops that sit in the bottom of the cup deteriorating in quality. The ideal grind can be sensitive to minor changes in room temperature and humidity, but usually, once set, the grind should only be changed if a new batch of (possibly older) beans requires a different grind.

Ground coffee starts to dry out and oxidise after just a minute - by ten minutes the crema will be non-existent and the flavour will be bitter. To ensure only the freshest coffee, it is appropriate to grind the coffee for just a second and discard the grounds resultant - this means the machine will only have fresh ground coffee left inside and the grind can begin again.

Tamping coffee is a controversial issue, mostly because so many home espresso machines have very little pressure and can't overcome a little pressure in the coffee beans. Good coffee will compress easily and for a high-quality machine, you should give it as much pressure as you can - even if that means jumping up and down. This gives a good even pressure throughout the mass of coffee in the group handle and ensures that the water that is pushed through it interacts with all the coffee.

Good quality water is essential for the process. Strong pollution or chlorine odours can ruin your drink. Coffee is known to be a good filter for heavy metals, but many other types of pollution will simply go through and end up in your cup, unbalancing the delicate mix of subtle flavours. Additionally, the chemicals typically found in domestic water supply can lead to lime build-up within the machine - not tasty and not good for operation! A simple charcoal filter jug can make a very big difference, especially if the water is also allowed to boil and then stand for a few minutes. But a ceramic filter is the best way of ensuring pure water. If the machine is not piped in to the water supply in the building, then the water should be replaced every day so the water doesn't become stale. It's also very rude to serve a Hindu a coffee made from week-old water.

The cup should be very small; Maxwell Williams make a good cheap coffee cup small enough for the task. Most espresso cups available at homewares shops are far too large to comfortably drink espresso without depositing the crema all over the side of the cup instead of in the drinker's mouth. If you have plenty of money and no children to break them, the small, thick cups available from good roasters are excellent to drink from. The cup should be warmed on the top of the espresso machine, or if it's only just been turned on, by filling it with boiled water.

When pressing the group handle into the espresso machine, it should go on easily and offer just a little resistance at the last moment - this is a sign you've just the right amount of coffee and the espresso machine is compressing the coffee just a little so you can get the group handle on. If the handle doesn't go on all the way, then you've put in too much, and you should scrape a little off the top with a teaspoon. Make sure the top of the group handle is free of ground coffee so that you can obtain a good seal. The water and steam should go through the coffee, not over the top of it!

As the coffee comes out of the group handle and into the cup, watch the colour of the coffee pouring from the espresso machine, with some attention to the colour of the crema in the cup. This stage is very difficult, with many fast decisions to be made.

Ideally, the coffee should be pouring out slowly, not dripping, but not running either. It will first be a line of thick black coffee, then settle into a very dark brown crema. If one side is noticeably better than the other, it is correct to move the cup to only collect the good coffee. Depending on the size of the pour required (ristretto or lungo), this might happen straight away or towards the end.

The pour is over when the coffee is a good size and the crema is still quite dark. How dark depends on the coffee beans, the machine and the taste of the drinker. The experienced barrista weighs all these factors while looking principally at the crema as it falls from the espresso machine. A good strong bitter ristretto is poured very quickly from the first side that the coffee first falls from; it's finished when the colour turns from dark brown to tan.

Once poured, the coffee needs to be consumed immediately. It takes a few seconds for the crema to settle, but by ten seconds after pouring, the bitter flavours begin to bite into the creaminess of the espresso. This can be somewhat counteracted with a tiny quantity of sugar (just a few grains on the edge of a small teaspoon can do the trick).

I serve coffee with a small almond flavoured biscuit, but I'll tell you about that some other time.

3 Comments:

Blogger CoCoCoCh said...

Cool post. What sort of brewing equipment do you use?

"just a few grains on the edge of a small teaspoon can do the trick"
Coffeegeek?


"the ground coffee holds together well, as if slightly moist. It comes out in bursts, rolling around into the group handle of your espresso machine"
doserless grinder?
I've found the plastic bits cause static buildup. Either modify it with an all metal chute or maybe an anti-static coating like use for spectacles?


"It's also very rude to serve a Hindu a coffee made from week-old water"
Huh?

12:13 am  
Blogger Rocket said...

I heart coffee.

I use a Gaggia Classic, which does all I need it to short of a $5000 professional machine with a $1000 grinder.

The grinder is good, but it has its weak points. But it's my boyfriend's...

Hindus don't drink water that's been sitting still. It's in the rule book.

6:34 pm  
Anonymous Stevo said...

I heartily recommend Kenyan Peaberry. Deep dark rich flavour with spicy tones.

Watch the balance between grind size and pull time. That's the "art" part =)

If you're doing a day "on the beans" for study etc, don't forget to secure some Lemonata. Great for cleansing the palate. If you can't hold a pen.. .switch to green tea ;)

Good luck with the study Kiddo :)

Stevo (LSS and K freak)

9:50 am  

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