If you love to keep a clean white smile, you should consider giving up your coffee intake. This is because coffee is known to cause stains on your teeth.
Coffee contains tannins which is a type of acidic polyphenol. It has the ability to cause discoloration and in turn cause problems for your teeth. Apart from these, the pigments from drinks such as coffee and tea can get stuck in the cracks of your teeth enamel and make them yellowish.
One way around this is to clean your teeth regularly after drinking such drinks.