There is one major component to keep an eye out for when sourcing green coffee for espresso. a)Flavour, b)Sweetness, c)Acidity, d)Body, e)Aroma. Which is the correct answer?
Sourcing for high quality green coffee is the first step that every roaster needs to go through before they even begin roasting. The quality of the greens dictate the potential of the final cup of coffee that we can create.
In this video, we talk about the most important attribute to look out for on the cupping table when sourcing greens for espresso coffees.
The answer: Sweetness.
There are two kinds of perceived sweetness present in coffee. The first one is what I like to call a brown sweetness. The second is more characteristically known as a fruit sweetness.
1. Brown Sweetness: As the name suggests, the brown sweetness has a resemblence to brown sugar or similar derivatives like caramel and chocolate etc. The brown sweetness is derived mainly from the caramelisation of sugars within the coffee. This process of caramelisation is known as the Maillard Reaction. The Maillard Reaction turns the sugars brown which actually REDUCES the sweetness of the sugars rather than actually increasing the coffee's sweetness.
If the caramelisation is reducing the coffee's sugar content and thus sweetness, why is there a common consensus that a more developed coffee is higher in perceived sweetness?
The reason is the degradation of acids within the coffee. As you continue to roast a coffee and caramelize it's sugars, the acids within the coffee breakdown at a quicker rate than the caramelisation of the sugars. The resulting lower ratio of acid to sugars within the coffee helps to increase the perception of sweetness.
Simultaneously, the increased caramelisation results in additional production of melanoidin (a by-product of the maillard reaction) and other heavy molecular weight brew colloids and oils within coffee that block our taste receptors and provide the perception of body. This further reduces the perceived acidity of the coffee and increases the perceived sweetness.
2. Fruit Sweetness: This is the inherent sweetness based on the sugars present in the green coffee. The sweetness should be reminiscent of fruits or flowers, hence the name. Ideally, a coffee with high fruit sweetness should remind you of ripe fruits, like a ripe mango or mandarin orange.
Although an improperly roasted coffee can affect the fruit sweetness present, you should generally be able to quantify on a scale from 1 to 10 how much fruit sweetness this coffee has. Sometimes it might taste more of unripe fruits or overripe fruits, which can be a result of the roast.
The key is to also watch out for the acidity to sweetness ratio. How well does the sweetness support the acidity? This will help you to better gauge the sweetness potential of the coffee. Remember to separate it from the brown sweetness, we are looking at only the fruit sweetness here.
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