For centuries, gold has been a go-to asset among investors worried about all sorts of financial risks. In the past decade, exchange-traded funds backed by the metal drew more money than any other commodity. Even the world’s biggest central banks hoard bullion as a reserve asset. But when it comes to inflation, which can erode the value of portfolios that don’t keep pace with rising consumer prices, anyone who bought gold as a hedge over the past 25 years missed out on a much better deal – copper. While data show that broad commodity indexes provided the best bang for the buck during periods of rising costs in the US, the red metal stands out.