What goes into making the perfect cup of coffee?

What’s better than a piping hot cup of South Indian coffee? The answer: a cup of coffee that’s not quite ‘piping’ — that is, coffee that’s served between 80 to 90 degrees celsius.

This came as a bit of a shock to me. For the longest time, the drill for making coffee in my South Indian household had been the same: put powder in the filter, press the plunger over the powder, add boiling water, and wait for the coffee to percolate into the lower container. Next, boil the milk, mix it with the coffee decoction, heat it some more, air it to build up some foam, and serve. And in what has become a standard practice, the coffee would be sent back to be heated some more after dad had taken a sip or two.

 And here I was, talking to experts who were telling me that the first mistake people make is expecting their coffee to be boiling hot. “You should be able to finish your Cappucino in 2-3 sips if required. That’s how hot your coffee should be,” said Gerson Aranha, CEO of Nilgiri Foods and Beverages, which supplies coffee beans to chains like Cafe Moshe’s and Mad Over Donuts.

“When you boil the water before pouring it into the filter, you are removing all the salts and the dissolved alkalinity. Water becomes flat,” says K Basavaraj, head of quality control at the Coffee Board of India. As I set about understanding the science behind South Indian filter coffee, I came to see that a range of compounds form the building blocks of the rich flavour and aroma that we enjoy. Brewing the perfect cup is really about extracting these compounds in the right proportions. My journey began with the beans.
 
Premium on peaberry
In South India, peaberry beans are considered a premium variety, unlike in Europe where it is considered somewhat inferior. Peaberry owes its fanatic fan following in India to its shape.
The coffee cherry (fruit) usually has two symmetrical oblong beans. As a result, the beans are flat on one side and rounded on the other. But sometimes one half develops more than the other. So, you get only one bean within the cherry, which is rounded all over. This is the peaberry and accounts for around 9-12% of the coffee crop.

“In the old days, when beans were roasted on a flat pan, the rounded beans would roast better than the ones which were flat on one side. Hence, peaberry beans yielded better coffee than the flat coffee beans,” says coffee coach Sahil Jatana, who conducts workshops on coffee brewing.

 So why do the Europeans frown upon it? The proportion of soluble solids in a coffee bean, i.e., the parts which get dissolved in water, determines the strength of the beverage. A peaberry bean has around 20-22% soluble solids whereas a regular flat bean has 22-26%. The coffee turns out slightly stronger when made using flat beans.

 The colour of the roast
Europeans also roast their beans to a darker shade to get stronger, more bitter coffee. Coffee beans start green, and are roasted up to varying degrees depending on the desired end result.

 “The cellular structure of the bean absorbs the heat, becomes hard and expands. At roughly 217 degrees, all chemical structure is lost, and a series of compounds start developing. The sweeter compounds develop first followed by the bitter compounds,” says Basavaraj. A light roast such as Cinnamon Roast gives a wider range of flavours, a greater caffeine content, and better aroma, but the percentage of soluble solids is lesser. Hence the coffee won’t be too strong.

 The City Roast is preferred for South Indian coffee. This is a medium roast, which provides a blend of flavour, aroma and strength, and yet not so bitter as to put off the Indian palate.
 Gravitational pull

The roasted beans should be ground to a powder of medium consistency — too fine or too coarse is not ideal for the South Indian filter. The filter itself is a simple contraption comprising two containers. The upper container has perforations and fits on top of the collection container. A plunger in the upper container holds the coffee grounds in their place. The water should be heated to 90-95 degrees Celsius — turn the flame off when bubbles start appearing at the bottom of the vessel.

Basavaraj also recommends wetting the powder with a tablespoon or so of warm water before pouring in the hot water. “Coffee is a fibrous substance. The fibres expand when they get wet, and the extraction will be free flowing.” Because of the gravitational force, the water passes through the coffee powder and collects in the lower container. The light, volatile compounds get extracted first followed by the oils towards the end. Hence, filter should not be disturbed during the extraction.

Add hot milk and air the coffee by rapidly pouring it from one glass to another — this is best achieved using a dabarah. The oxygen in the air mixes with the coffee to release the volatile aromatic compounds.

Here my journey ended — my senses taking in the aroma of freshly made coffee, and its rich flavour. The difference was that I knew what exactly goes into the making of it, down to the last compound.