I have previously experimented in setting methods and found that heat can be handy. This makes sense, as commercial wool is fixed into its final twist using “heat setting”. The process is basically steaming at high temperatures in order to stop torquing, i.e. that annoying wrapping around itself yarn does when freshly spun or plyed.
This process is relatively easily replicated in the kitchen, with a wooden spoon and a pan with a lid.
Wind the freshly spun single or freshly plyed yarn around the middle of the spoon handle, then secure the loose end, I used a hair bobble. Now bring some water to the boil in the pan (add a pinch of salt to increase the maximum temperature), balance the spoon over the top, and balance the lid so it half covers the pan.
Fixing a single takes a lot less time than fixing plyed yarn, with the small amount on here the single took 25 minutes and the plyed 2 hours. I think the wool was previously heat treated, though, and experiments with pure wool, previously untreated, were quicker and resulted in a nice, lofty yarn.
Below are (in order of appearance) previously heat treated and home dyed wool, merino-nylon blend and two commercial yarns I plyed together and heat set.
The synthetic blend and previously treated fibres react very well to heat setting in terms of not torquing, but they lose their stretch and softness. The pure wool did not, it stopped torquing and remains as soft and squidgable as the two yarns that make it up. It is not at all scratchy, or felted.
The safest way to set the twist, of course, is to leave it on the bobbin to rest, but if the process needs rushing, heat setting seems like a way forward!