of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. Water doesn’t get ‘cleaner’ on its own. Semi-permeable membrane
of water-chemistry approach - hard water ◦ ‘Blank slate’ ◦ vs Modified tapwater ◦ vs Bottled water • ‘Edge case’ of an edge case • Non-brewing utility • Waste water