Since there are no choices given, my answer might not be what you're looking for. But it can definitely be a correct answer. The technique is called filtration. Filtration is a physical separation to separate the liquid and solid in a mixture. The mixture should be composed of an insoluble solid in a solvent. The mixture is usually passed through a semi-permeable barrier. In this case, a special piece of paper is used. The solvent is the liquid and the solid is the coffee bean grounds. Only the liquid can pass through the paper. The liquid that passes through the paper is generally called a filtrate.
