Why do your instructions say : “Do not allow filter to freeze?”
We strongly advise against freezing your elements as a general rule of caution. We also advise against storing the elements (even unused) in sub-freezing climates. The concern with freezing the elements is that any cold or freezing water will expand inside in the element, thereby increasing the pore size and ruining the element. Whether the elements are unused or used and fully dried out, a small amount of moisture could still exist inside the element, especially in predominately humid climates. This moisture could expand inside the element and render them unusable. Please note that this recommendation applies to ALL our Berkey® elements, including the Sport Berkey® water filter bottle element. Freezing your element and rendering it unusable will also void your warranty coverage.