Eggshells
I don't know if you've heard of putting a teaspoon of eggshells in your coffee grounds but I've recently started trying this method. I first heard it about it while listening to a podcast with Brett Terpstra.
The idea is that the alkaline nature of the eggshells helps offset the acidity of the coffee during the brewing process.
I think it works splendidly and would recommend it to anyone looking for a smooth taste of coffee through the whole drink. No more bitter after-bite. Obviously this is more pronounced with some coffees.
Using only eggshells that ARE NOT hard boiled, wash them with hot water and peel out the inside lining so they are nice and clean and set them out to dry. Once they are dry, crumble them up and store them however you wish for use later.
When you put your coffee in the filter, top it off with a teaspoon, approximately one egg worth of shells.
I can taste the difference. Can you?