Arabica vs. Robusta
When it comes to commercial coffee bean production, there are two main species of coffee plant, Arabica and Robusta. The former is generally favoured over the latter as Robusta tends toward bitterness. Some tasters will also tell you that it has less body and flavour. You’ll find Robusta coffee as a relatively inexpensive substitute for Arabica in many commercial coffee blends. A good quality Robusta is sometimes used in espresso making, where it delivers a creamy head but also lowers production costs. Arabica on the other hand, has a deeper, more subtle flavour that can stand on its own, not as part of a blend.
What makes a good cup of coffee?
Making a good cup of coffee is a fine balancing game that depends on:
The bean: single origin vs. blend
The balance of crucial flavour-imparting elements of acidity, aroma, body and flavour are contained in a single bean. Thus, when making use of single origin beans there is little leeway for adjustment that would have otherwise been achieved through blending.
Each sub-species of Arabica or Robusta plants, growing under different conditions worldwide, require their own, unique roasting method to achieve a harmony of the 4 flavour imparting elements. Each has an optimal roasting balance. Fine beans can be destroyed through being roasted too long or at too high temperatures, which leaves them burnt and bitter – This is why beans hand roasted in small, quality-controlled batches generally produce the best results.
To get a good cup, the grind – how finely or coarsely beans are ground prior to brewing – needs to be suited to the brewing method. Too coarse, and you will get coffee that is ‘underextracted’ or weak and too fine, the resulting coffee is ‘over-extracted’ and unpalatably strong.
Who is at the controls?
The knowledge of the person brewing the coffee – the barista- is paramount,for it is they who control the degree ofthe grind, the correct ‘tamping’ (howhard to pack the coffee in the holder)and the temperature and duration of brewing.
A coffee machine controls the water heat, pressure and appropriate amount of time used to brew a cup of coffee. For example the optimal amount of time it should take to produce 30ml of espresso is 25 seconds. More than that and the beans become scorched (over-extracted) giving a burnt taste; less than that and the resulting coffee is without body and weak (underextracted). Temperature is a critical factor. It is important that coffee be expressed using scorching water – but not boiling, which burns and overextracts. A temperature of about 95°C is optimal.
The crema, a nice Italian word, is a natural foam that is produced by the extraction process under the correct pressure, about 9 Bars. Ideally, a crema which has fine bubbles, appears rich and thick and is a reddishbrown, is the one to strive for. White spots appearing in your crèma is an indication that the coffee has been over-extracted.
Common brewing mistakes When your cup of coffee tastes burnt, it could be:
• over roasted beans.
• Grind too fine;
• Water temperature too hot
• Processing took too long
• If using a drip filter, leaving the coffee for more than 30 minutes on the heating pad will burn your coffee
Once you’ve paid around R100 per kg of single origin East African Arabica, you want to keep it at its aromatic best by storing it properly. Coffee oxidizes and goes stale very quickly. Effective storage therefore requires an airtight container in a dark cupboard or freezer. Contrary to common practice, avoid storing coffee in the refrigerator – fluctuations in temperature caused by the opening and closing of the door create condensation – moisture which leeches he essential oils from the bean.
Once roasted, coffee will keep fresh for up to two months. Once opened, a sachet of ground coffee will last about 2 weeks before beginning to deteriorate.
The crema, a nice Italian word, is a
natural foam that is produced by the
extraction process under the correct
pressure, about 9 Bars. Ideally, a
crema which has fine bubbles, appears
rich and thick and is a reddishbrown,
is the one to strive for. White
spots appearing in your crèma is an
indication that the coffee has been