You might have wondered why you have 300 over views and no replies.
Lipids or also more commonly oils, which are by the way sold as a cooking ingredient for salads and stuff, have nothing to do with Colombia alone.
Each bean releases these oils, no matter where they are from.
The Coffee bean contains oil just like soy or peanut.
During the roasting process the cell structure will be harmed, as the temperature changes are fast.
The bean has immense pressure as the heat first seals off the surface.
So actually the bean seals it self.
During Roasting there is high pressure in the bean and that leads to a different environmental change within the bean and greatly influences the chemical processes and reactions.
I have explained more about this here. http://www.coffeeforums.com/viewtopic.php?t=579
In another thread before someone asked how to avoid the oils to come out.
You can’t there is a price to pay if you want too.
I can roast coffee at 198 degree fpr an hour or so.
Acidity will be drained and such but at the price of aromas. There will be no oil, but its simply a lousy roast.
To make that short, there are many factors in regards to the oils, the most important one is heat, how fast and how much.
In order to measure heat you have to have pile temperature taken.
Pile temperature is the temperature that is the mixture of supply temperature and bean temperature. You can minimize oils, but you can not avoid them once you go darker. Even you might drop a dry bean, have a look at it 2 days later and you’ll see them sweating maybe not all but some, it’s a matter of grading too.