“Should you brush your teeth before or after coffee?”

After coffee is the best time to brush. The coffee is more likely to stain your teeth the longer it has contact with them. So, if you are only brushing once, brush after you have had your coffee.

I would recommend that you brush 30 minutes AFTER having coffee. After consuming anything but water your oral cavity is preparing its defense. Plaque acids are increased while eating and drinking. The research indicates it is BEST to brush your teeth 30 minutes after eating and drinking. You could also consider rinsing your mouth out with water when you finish your coffee.

Best approach is to rinse your mouth with water to dilute the acid in the coffee and then brush after coffee.
Hope this is helpful.