In African countries, food security greatly depends on farmers' propensity to store grain until the lean season. Using original data collected from 1,500 farmers in Burkina Faso in 2013, we show that individual risk and time preferences play a central role in grain storage decisions. We use a sample selection model as well as a structural estimation approach and find that both lead to very similar results. Specifically, we find that a one-standard-deviation increase in the discount rate (resp. risk aversion) results in a large decrease (resp. increase) in grain storage of about 45% (resp. 25%). We simulate a grain price stabilisation policy and show that half of farmers in our sample would benefit from such a policy.