>>2543177winter (below freezing temperatures) will ruin fiber based filters like Sawyer as well. People are praising "graywater filters" as providing greater pressure with your hands you can actually filter viruses as well. All I know I have neck baggies I can put my sawyer mini in and have partial filtration while those type of big bottles with attached filters would freeze in my backpack
I had water partially freezing in my backpack after as little as 6 hours outside before
