In general, you have 2-4 hours until oxygen absorbers become fully saturated. However, our recommendation is that you use them or store them within 15- 30 minutes after opening. As you know these are oxygen absorbers and 21% of air is oxygen. Therefore, before opening the vacuum seal, you need to be prepared to use them to store your food and seal them quickly. Also you need to store unused oxygen absorbers in a mason jar or vacuum sealed bag. Because it's a vacuum seal package, once it's opened, it is not resealable. You need to have a vacuum sealer to vacuum seal unused oxygen absorbers. It is important to have as little air in contact with them as possible. Please use a  small jar to best fit unused oxygen absorbers.