I have been roasting coffees for over 3 years now and have been very fascinated about the chemical changes that the beans go through during roasting. Roasting is fun and becomes more mystical and interesting when you start seeing the chemical changes that beans go through when the roasting begins. Most coffees that we see in Kathmandu is roasted dark where all the aromatic compounds within the beans are diminished away during its conductive or convective heat transfer in roasting.
I am personally not a fan of Dark roasted coffees but when I see coffees being roasted in dark oily profiles the possibilities for its flavors to shine in the cup is almost zero. Espresso or Filter coffee I believe the coffees need to have some depth of flavor and balance which should not be dominated by only one prominent flavor which in most cases would be "Roasty, Charry, Rubbery, Burnt, Bitter". Most people associate the word " Strong Coffee" with Dark Roast which i think is a misconception. I believe Nostalgia is one reason why people go for those roasty flavors because most of our taste buds have been inclined more towards instant coffees in Nepal. My understanding for Strong Coffee would be purely based on how i prepare my brew and play with my brew ratios; be it espresso, filter or V60s.
In my roasting experience most Nepalese Beans can have those Caramelly, Nutty, Chocolaty, sweet notes if roasted in Medium to Medium dark profiles provided the beans have been processed carefully at the farm and developed properly during roasting. As a roaster one has to be knowledgeable enough and should learn to understand the beans before roasting. Parameters like Density of the Green Beans, the way it was processed( Natural or dry) , the moisture content, and the terroir of the beans all play important roles in roasting. Density would be one important aspect in roasting since it paves the way for how much conductive heat to apply during the first phase phase of roasting. I will be dedicating a blog on Roasting in my coming blog where i will cover the basics of Coffee Roasting and things to consider before you roast.