I half filled my water bottle yesterday morning, prior to riding to work.
The first use of the bottle was fine. After about 20 minutes though, it got a bit hard to suck water out of.
Got to work and examined the bottle. A quite thick skin of ice had formed inside the bottle and the water had lots of ice crystals floating in it.
The loooooooooooooooooooooooooooooooooooong hot shower was nice though
