Question

What is percolating up and percolating down?

Answer 1

to cause (a solvent) to pass through a permeable substance (such as a powdered drug) especially for extracting a soluble constituent. b :to prepare (coffee) in a percolator. .....percolate up

to cause (a liquid) to pass through a fine mesh, porous substance, etc., or (of a liquid) to pass through a fine mesh, porous substance, etc.; trickle........percolate down