how to wind yarn

I have had a couple people ask me, why do I need to wind yarn into a ball? Doesn't it just come ready to knit? Well, some yarn does. Most of the yarn that one buys in a craft store is wound into a center-pull ball, so that you only need to find that center strand (often harder than it looks!) and go from there. But, if you purchase hand-dyed or higher end yarns from a local yarn store, then most likely the yarn will come in a skein, which is a fancy name for a big loop of yarn twisted up on itself to look pretty and display the colorway.
So, in picture form, here is what the yarn swift is for:
This is a skein. See how it looks sort of braided? In this skein, then ends are actually tied together, and have to be untied or cut before winding into a ball. (I will show this later) As well, there are several other points where the yarn is tied. This holds the yarn together during dying.
This is a purewool colorway called diante.

On the right, you can see a skein of yarn as compared to a center-pull ball that I previously wound, using the awesome yarn winder and swift. Bri built the swift, the yarn winder came from Knitpicks. As far as I have seen, they have the best price on yarn winders. However, they do seem limited to winding a ball of about 6 oz. Much bigger than this and the ball sort-of loses its neatness and is prone to tangling. I don't know if using a more spendy winder would solve this issue.

Here is the skein un-wound into a giant loop. You can see the places where the yarn is tied to hold it together. If I didn't have a swift, then I have to find something else to loop the yarn around in order to wind it up. Spinny office chairs work well, as do baby gates, as you can adjust the width to fit the yarn. A husband's arms, or your own knees, work, but less well, as there will be a tendency to get tired in the time that it takes to manually wind yarn.
Here is the yarn all stretched out on the swift. The swift has a bolt in the center which allows it to spin freely, so the yarn can be easily pulled off. The TV tray is too small for the swift, so I used bungee cords to keep the swift from falling over. For reference, this loop of yarn is almost two feet in diamiter!
I did not take pictures of the actual winding process (perhaps a later post?) But basically once you find the end of the yarn and cut all the ties that hold the yarn together, you grab the end of the yarn, attach it to the winder, and turn a crank. The yarn winder looks very much like a fishing reel- in fact I wonder if a winder could be made from a reel- it would be cheaper if you could find one at a garage sale! I have seen winders made from legos, tinker toys, electric drills, and electric mixers as well.
Hopefully you found this helpful!