Discover the Rich Flavours of Mahalia Coffee
The Art of Developing Flavour Through Roasting
Roasting is where the magic happens. What starts as a raw green seed dried, cleaned and sorted from the fruit of a coffee plant is transformed through heat into the aromatic, full-flavoured bean you grind every morning.
At Mahalia Coffee, our roasters use precise temperature and airflow control throughout every roast to coax out each bean’s sweet spot — whether that’s bright berries, smooth chocolate, or rich toffee. It’s a craft that takes years to master, and one we never stop learning.
The Three Stages of Roasting
1. Drying Stage
Green coffee beans arrive with a moisture content of around 10–11.4%. The first job is to rapidly reduce that moisture — typically over 3 to 8 minutes in a drum roaster, depending on batch size. By the end of this stage, the bean reaches around 160°C.
Getting the heat right here is critical. Too much too soon and you risk scorching the outside while the centre stays underdeveloped. This stage also builds energy in the bean, important, because the final stage of roasting is exothermic (heat-producing).
2. Browning Stage
From 160°C, something wonderful starts to happen. The beans begin to smell like baking bread then warm vanilla cake. These are aroma precursors converting into aroma compounds, the building blocks of flavour.
Towards the end of this stage, the Maillard reaction kicks in. Sugars and amino acids react to create hundreds of distinct aroma and colour compounds. This is when the roast naturally slows and where a skilled roast master earns their keep, carefully managing the rate of rise to ensure optimum flavour development. The stage ends with a distinctive sound: the first crack, signalling the bean is ready to enter development.
3. Development Stage
The first crack marks the start of the development stage, where the reaction turns exothermic and the bean releases the energy it’s been storing. This is when the most desirable aroma compounds form.
Development time typically accounts for 15–20% of the total roast time, depending on the desired flavour profile and roast degree. Rush it, and you risk a smoky, sharp cup. Nail it, and you get coffee that sings.
Roast Degree
Roast degree is one of the most important decisions a roaster makes and it shapes everything about how your coffee tastes.
Light roasts tend to be more acidic and fruity, with flavours that reflect the origin of the bean. A compound called 5-hydroxymethylfurfural is responsible for those bright, fruity notes and it breaks down as roasting continues. Dark roasts develop deeper cocoa and roasty characteristics, but push too far and you lose the nuance, ending up with flat, smoky, tobacco-like flavours.
At Mahalia, we measure roast degree by time, temperature, colour and cupping because no single measure tells the whole story.
Roast Time
Temperature plays the largest role in flavour development, but total roast time and the time spent in each stage matters just as much. A shorter roast can produce more desirable aroma compounds, but only if the bean develops evenly throughout. Underdevelopment in the centre is one of the most common roasting faults, and one we work hard to avoid.
A well-planned, well-executed roast brings out the full complexity of a coffee, the fruity, chocolatey, nutty notes working together rather than competing.
Roasting for Filter or Espresso?
Filter and espresso are extracted very differently and that changes how we roast.
Filter relies on gravity for a gentle extraction, which suits more aromatic, acidic coffees beautifully. Espresso uses around 9 bars of pressure, extracting more flavour from the same bean — which means a coffee that’s too acidic or delicate can become overwhelming in the cup.
Rather than roasting exclusively for one method, I aim for a golden middle ground, a roast degree that works beautifully as both filter and espresso, without compromising either. It’s a philosophy shaped by years at the roaster, and one that I think makes Mahalia coffee genuinely versatile.
Roasting is a never-ending journey. Every bean has more to teach you. And finding the best possible roast profile for each coffee — that’s still the most interesting part of my work.