How to concentrate for exam? In order to concentrate, stimulate the brain, increase and strengthen memory power, a cup of Dr Kalan coffee will help you for your concentration, learning and consciousness. Dr Kalan coffee releases energy slowly which helps you remain energized throughout your exam and your studying and during your class. Remember high doses of Caffeine (like in regular Coffee), will start your hands to tremble and will actually make it harder to concentrate and will make you jittery.