Water bottle cozies

The coffee machine at work broke this summer. This wouldn't have been much of a problem, except that I relied on it to supply me with ice cold, filtrated water as well. With no replacement in sight and the tap water there pretty much undrinkable, I had to solve the problem myself. So I started freezing a half full bottle of water at home and bringing it to work.
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Now, this worked just fine, but I noticed a couple of things I knew I could find a solution to.
First: A bottle of ice water is, well, cold. No surprise there. Which made my fingers cold, which made my patients jump and twitch when I touched them, which, in turn, made taking x-rays of them a little bit tricky.
Second: If I left the bottle on a desk somewhere and didn't come back to it for an hour or so, it would collect quite an impressive puddle of condensed water. Which was merely inconvenient when the water dripped down my uniform making it half transparent, but really quite dangerous when the water gravitated towards electrical stuff (and that stuff's pretty much everywhere in a radiology ward).
Third: On hot days, there just wouldn't be enough ice to last the shift, even if I froze the bottle nearly full.
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The bottle cozy not only keeps the water cold for longer, but is also nice to the touch and completely eliminates condensation. I brought it along on a canoe trip this summer, and enjoyed ice cold lake water the whole day, to the slight envy of my friend. I made her and her husband one each for christmas. :) Also, my cousin got one, but I seem to have forgotten to photograph it... Not a very exciting object, I suppose. I've got two myself, one for the 0,7 litre Imsdal bottle, and one for the 0,5 litre bottle.
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How to make them, you ask? Well, it goes like this. Find a medium to thick yarn of 100% new wool, a hook that's one size smaller than recommended for the yarn. Make a tight spiral for the base, and just stop increasing when you start the wall. The cozy should be slightly wider and taller than your bottle (that's a precise technical measurement term, that). Hand felt in soapy water until snug (testing the fit regularly) and allow to dry on the bottle (refilling the bottle with warm water now and then speeds up that process). Ta-da, enjoy ice cold water anywhere. :) Ravelry links one, two, and three.
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