Caffeine is stable at temperatures below 235°C (455°F), and few coffee roasters would roast a coffee past this temperature due to the risk of fire.
So caffeine content remains pretty much constant throughout each stage of the roasting process.
Q:Is a cup of dark roasted coffee has more caffeine?
A cup of dark roast coffee will probably contain more caffeine than a cup of light roast. What? How?
It’s all to do with the density of the coffee beans. As coffee is roasted darker and darker, the beans lose mass. But despite the loss of mass, the caffeine content stays the same. So it has higher caffeine content w/w, by ~ 5% to 9%
If you brew a cup of coffee, whether it is a light or dark roasted, using same weight of roasted beans, the caffeine per cup will be slightly higher in a dark roasted coffee.
The main reason that people think dark roast coffee has more caffeine is because of the increased bitterness and kick, which is associated with caffeine.
It’s true that caffeine is intensely bitter, which is why it’s often cited as the reason that coffee is bitter. However, caffeine only accounts for a fraction of the bitterness in arabica coffee.
The reason that dark roast coffee tastes so bitter is because of the chemical reactions that take place during prolonged roasting. The longer a coffee is roasted, the more that certain acids turn into bitter-tasting compounds.
You’ll notice that dark roast ( vienna or french roast) coffee is almost black. That’s because it’s essentially burned, which is why it has that harsh, ashy, bitter taste, but very rich in coffee aroma
Arabica vs Robusta
A single unroasted arabica coffee bean has 1.9 milligrams of caffeine. By dry weight, an arabica coffee bean is between 1.2 – 1.5 percent caffeine, meaning that it contains 1.2 – 1.5g of caffeine per 100g (3.5oz).
A single unroasted robusta coffee bean has 2.9 milligrams of caffeine (2.5%) (2.2 – 2.7g of caffeine per 100g).
caffeine content in different drinks:
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