Market models and so-called string models for commodities have been widely used in industry. These approaches exactly match the current forward price term structure and traditionally model forward prices as multivariate GBMs. Here, I introduce a new approach where I model the discrete forward cost-of-carry directly rather than forward prices themselves. Through a sequence of measure changes, I demonstrate how to calibrate calendar spread options, options on forwards and forward prices all at once. Furthermore, I explain how unspanned stochastic volatility and jumps can be easily added into the modeling framework.