COMMODITY BUBBLES. Harvard's Jeff Frankel explains the economics of easy money and commodity price increases.

A monetary expansion temporarily lowers the real interest rate (whether via a fall in the nominal interest rate, a rise in expected inflation, or both – as now). Real commodity prices rise. How far? Until commodities are widely considered “overvalued” — so overvalued that there is an expectation of future depreciation (together with the other costs of carrying inventories: storage costs plus any risk premium) that is sufficient to offset the lower interest rate (and other advantages of holding inventories, namely the “convenience yield”). Only then do firms feel they have high enough inventories despite the low carrying cost. In the long run, the general price level adjusts to the change in the money supply. As a result, the real money supply, real interest rate, and real commodity price eventually return to where they were.

There is money to be made, if one is able to be among the earliest to join the "widely considered" set.