How soon after mixing Perpetuem and Sustained Energy do they need to be consumed?

In moderate temperatures, a pre-mixed bottle of Perpetuem or Sustained Energy should be suitable for consumption for up to 5 hours, perhaps even slightly longer. In warm-to-hot weather, that consumption “window” will be shorter, as short as 2 hours in very warm weather. Freezing your pre-mixed bottle(s) of fuel the night before will extend their palatability (i.e., staying colder longer) and keep the mixture suitable for consumption for a longer period of time.