How did my wool get over plied?

I recently spun some lovely wool and was very happy with it until I plied it. Wow! is it way over plied. I don't understand why. When I'm spinning I let it twist back on itself occasionally to check my twist and it didn't seem overspun or underspun. Any ideas what I might be doing wrong and how I can fix this? A: You do not say if you had washed the yarn before you were concerned that it was overplied. The reason I ask is that it is very common for the twist in singles to go dormant while it is on the bobbin. This happens for many reasons, some are humidity, cleanliness of the fiber, amount of twist, and/or the amount of time it takes to finish spinning the bobbins for the project. Then when the dormant single is plied, the resulting ply looks twisty and is often regarded as overplied. The good news is that the singles twist is just dormant and not doing it's share in balancing the plying twist. When the yarn is washed the twist in the singles will be rejuvenated and often appears to magically balance the plying twist. Perhaps you have already washed the skein in question. If not please do so. Be sure that it is properly tied in three or four places so that the skein can be opened out after washing. After it is washed and rinsed, blot out the excess water, and then put your arms inside the skein to snap it open several times. Now hold the skein at the top and look at it while it is damp. If the skein is turning with several twists it might need a plying adjustment. However if the skein only twists once on itself it is probably fine. To adjust a damp skein that twists several times on itself, look at the way it crosses, is it with an S or a Z twist? If it crosses with an S twist it is underplied and needs more S plying. If it crosses with a Z twist it is overplied and needs a bit of ply removed by running the spinning wheel in the Z direction. The direction that the damp skein twists is the direction you should turn the wheel when correcting the skein. I usually do the adjustment while the skein is damp. This way I know that all of the twist is lively and active. I place the damp skein on my swift, untie it at all points and quickly run the skein into the wheel in the direction indicated. While it is damp you can do the "drape" test by letting the yarn hang in a simple loop. If it hangs without twisting S or Z then it is a balanced yarn. If the yarn is dry, when you do the drape test then you may have a false reading from dormant twist. One other consideration is the drive system on your wheel. If it is a double drive, the test should be done after the yarn has proceeded into the bobbin. Since double drive wheels pull the yarn in slowly it will gain more on the way into the bobbin if you check a length in front of the orifice. With other wheels the check can be done on yarn just before it goes into the orifice, since they can be adjusted to pull the yarn in quickly during this exercise.