Actually, the roasting levels differ in brightness. The shorter the beans have been roasted, the lighter they are. Light roasts have pronounced acidity. With medium roasts, the acidity is still noticeable, the taste is balanced, and the body of the coffee increases. Darker roasts emphasize the body of the coffee more; the acids decrease, but so does the variety of flavours. On the other hand, dark coffee highlights the bitter-sweet roasting note more strongly. Lighter roasts indeed have more caffeine than darker ones. However, darker roasts are usually used for espresso and similar drinks. Therefore, you drink them much more concentrated than a light roast, which you would rather brew with a filter. An espresso is therefore comparable in caffeine content to a cup of filter coffee.
From light to dark, the coffee goes through the following roasting levels:
Roasting levels at a glance
Light Cinnamon
which forms even before the first crack.
Cinnamon
light colour that occurs with the first crack.
New England
at the peak of the first crack.
American
a medium brown that you achieve with the end of the first crack.
City / City+
Reach it between the first and second crack.
Full City / Full City+
is a darker brown that you achieve just before the second crack.
Vienna Roast
You achieve this with the second crack. Small oil droplets form on the bean.
French Roast
is already very dark and the surface shines, the second crack is coming to an end.
Italian Roast
is even darker, and the beans shine brightly.
Spanish Roast
(also known as Neapolitan) is the darkest roast level that you can still drink, the beans are almost black and matte.
Briquette
You can use it to grill your sausages ;-)
A serious note:
Be careful not to let the beans catch fire in the roaster!
You must always be present at the roaster while roasting.