My home roasting experiences

The first thing you might notice when you go to a coffee shop is that there are light, medium and dark roasts . What's the difference? Roasting is what makes green coffee beans into something you would want to brew. The heat of the roaster causes a series of chemical reactions; the end products are the aromatic compounds that give coffee its distinctive aroma and flavor. The longer you roast the beans, the darker the coffee gets.

Different blends work best with particular roasts (strong, medium, light). It is the roasting which brings out that wonderful aroma and rich taste that pcoffee lovers seek. These small, gas-fired horizontal drum roasters are normally used by the smaller coffee specialists who need a great deal of experience and even instinct to attain the exact desired roast, using sight, taste, smell and the sound of the beans crackling as they're tossed in the revolving drum. There are a few rosters in Singapore that you can view.One of them is definitely Cuppachoice at Temple Street, we also have Highlander at kampung Bahru and Papa Palheta at Hopper Road.

Temperatures for roasting range from about 193 degrees (about 380 Fahrenheit) for a light roast, through about 205 C (about 400 F) for a medium roast, to about 218 C (about 425 F) for a dark roast. Once the roasting is completed, the beans are transferred to mesh trays for rapid cooling which halts the roasting process. I've viewed several live roasting already.

During the roasting process the beans pass through different stages. Firstly the water contained in the bean evaporates. Then the bean swells to twice its original volume which causes the silvery coloured skin to break and fall off (this is the chaff that is removed from the roaster at the end of the roasting process). The colour of the bean changes from light green to yellow, to yellow-brown, to light brown and then to dark brown. The coffee aroma develops from a series of chemical reactions as the bean is roasted. In its green form the bean has virtually no aroma.

There are many different roasts of beans available on the market but the following guide lists the main categories and their common names.

DARK ROASTS (14 MINUTES)

The darkest roasts such as Italian Roast are also known as "Heavy Roast", with beans roasted nearly to jet black giving a smoky well roasted taste which masks the natural flavours of the coffee bean.

MEDIUM DARK ROASTS (12 TO 13 MINUTES)

Medium dark roast is when the beans are roasted for a long time at a high enough temperature to bring the natural oil of the coffee to the surface.
Some examples of medium dark roasts are:

French Roast - which is also known as "Dark Roast". French Roast beans are often used to make espresso.

Continental Roast - which is slightly lighter than French Roast but with spicy body.

Viennese Roast - which is roasted a little longer than regular American roast and has rich chocolaty body.

Full City Roast - which is even darker than City roast.
MEDIUM ROASTS (9 TO 11 MINUTES)

Medium roasts balance body with flavour.
Some examples of medium roasts are:

Breakfast Roast - which is a bit sweeter than a light roast.

American Roast - which is not as dark as any of the European roasts but has a good aroma.

City Roast - which is darker than the standard American roast.

LIGHT ROASTS (7 MINUTES)

A light roast gives a very subtle light bodied flavour.
Some examples of light roasts are:

New England Roast.

Half City Roast.

Cinnamon Roast - where the surface of the bean is dry with no oils present and flavour is light-bodied.

This is what I think, Light roasts retain more fruitiness and the subtle more complicated aromas. Because they have a weaker flavour they can be made very generously for a creamy cup, provided thay are not too acidic.
A medium roast is more general purpose, producing a stronger coffee flavour. Acidity becomes tang (or bite depending on your choice of language) while the smoother types of coffee gain a general strength without becoming bitter.