Yes normally you can preserve your DIY shampoo up to 6 months in the freezer. Be aware that it may separate your shampoo, change its texture a bit or make it a bit less effective. Also, you make sure to check for any changes in smell, colour, or texture prior to using your defrozen shampoo. Our tip is to freeze the shampoo as ice cubes so you only have to defrost what you plan on using. Freezing and unfreezing your shampoo many times add risks of bacterial growth and often reduces the efficacy of the shampoo as well so we recommend avoiding that.