We do recommend warming or thawing TeSR media or supplements in the fridge overnight, or at room temperature instead of at 37°C. There is a large temperature discrepancy from storage at -20°C to thawing in a 37°C water bath. Components may precipitate with such a large temperature change, and more importantly, this may affect the performance of the components. Once the supplement is thawed, use the supplement immediately or aliquot and store at -20°C for up to 3 months. After thawing the aliquoted supplement, use immediately or store at 2 - 8°C for up to two weeks, and do not refreeze.