Then we were at Starbucks the other day, and I saw a glass water bottle sheathed in some sort of plastic or silicone, to be less breakable. So I thought, why can I not make a cover for my humble canning jar, so it can go places with me? And the idea for a water jar cozy was born.
So I'm putting the (very simple) pattern here in case anyone else would like to make one. You will need about an ounce of worsted weight cotton yarn, a size F crochet hook, and a hair elastic.
Abbreviations in this pattern:
sl st = slip stitch
ch = chain
sc = single crochet
dc = double crochet
Round 1: Sl st into hair elastic, ch 3, then dc 35 into hair elastic. Sl st into top of ch-3. You should have 36 stitches if you count the ch-3 as a dc. (This is the top of your cozy.) Do not turn your work at the ends of the rounds.
Rounds 2-8 - Ch 3, dc in each dc, sl st into top of ch-3. Again, you should have 36 stitches counting the ch-3.
Round 9: Now we begin decreases for the bottom. Ch 3, dc 1, dc 2 tog; *dc 2, dc 2 tog* to end of round. Sl st into top of ch-3. (26 stitches, counting ch-3.)
Round 10: Ch 3, dc 2 tog; *dc 1, dc 2 tog* to end of round. Sl st into top of ch-3. (18 stitches, counting ch-3.)
Round 11: Ch 3, dc 2 tog; *dc 3 tog* to end of round. Sl st into top of ch-3. ( 7 stitches, counting ch-3) Fasten off. Use yarn tail to sew up the hole as you weave it in. Weave in top tail also.
I like a handle on my water container. If you would like one as shown, make a chain about 2" longer than you want your handle to be. (Mine is about 15".) Now you're going to sc on both sides of your foundation chain: Sc in the back loop of the second ch from hook, and in back loop of each remaining ch. Sc 5 in end ch. Turn and sc in the remaining loops of your foundation chain. Sc 4 in the end loop, and sl st into first sc. Fasten off. Stitch the ends very securely to sides of your cozy - if you made your yarn tails long enough, you can just use those for the sewing.
If you make one of these, then you are a pattern tester. :) Let me know if you find any mistakes, or if you think of a way to make this clearer.
Edited 2-22-11 to clarify abbreviations.
Update: here's the second, in ecru, with a leaf applique. The leaf pattern is from Crochet with Raymond, and can be found here. Here's the ravelry link, if you prefer.
One commenter asked for a photo of the bottom, to help understand the instructions. Here you go!
(And by the way, these are the same two jar cozies - I'm still using them, almost 4 years later!)