Once you've mastered the basic technique, discovered the optimal temperature and pressure for your home carbonation system, which are as important as the addition of minerals, it's time to amass a collection of salts. You'll want table salt (NaCl), sodium bicarb (NaHCO3) and Epsom salt (MgSO4) along with the slightly harder to find calcium hydroxide (Ca(OH)2) and milk of magnesia (Mg(OH)2). (Skip the bath salts, people, they're not even salt.) Martin Lersch of the blog Khymos has done the dirty work and you can download his mineral water calculator for Perrier, Gerolsteiner, and Vittel. Darcy O'Neil, in Fix the Pumps, also offers advice. With enough of the right calculations, you too can master the finest of European bottled waters, without every making a trip overseas.