Scott Moss: Shepherd, wool processor, dyer & spinner
There is lots of advice about scouring to be found on YouTube and various other websites. If you have a fleece, it is expensive and sometimes a waste of money to send it to a commercial mill for processing. We have had fleeces returned as very greasy carded batts. As the mill in question would not send the processed fleece until we had paid, there was not much we could do about it. However, we do know of a good mini-mill run by a lovely couple. They are not cheap and their turnaround time (from receipt by them to return to you) is really quite long.
Preparation for scouring
A shorn fleece, at least those from our sheep, is typically dirty with the sheep's sweat and dust held by the grease of the fleece as well as bits of vegetation picked up over the course of the year. It saves considerably on the cost of scouring agents if the fleece is soaked in water for a day or two before scouring. I generally change the water and continue soaking until the rinse water becomes clear. The water can be at ambient temperature outside. If I am not going to dye the wool with natural (as distinct from chemical) dyes, mains water is entirely suitable for scouring of any other part of the process. For purposes of natural dying, however, it is usually important to avoid using water that is either strongly alkaline or strongly acidic since these will affect the resulting colours. We have a 2000-litre rainwater tank and I have tested the rainwater for its pH-value which is close to 7 meaning that the water is neither alkaline nor acidic. If we didn't have an ample supply of naturally pH-neutral water, I would raise the pH-value of acidic water by adding citric acid or clear vinegar and lower the pH-value of alkaline water by adding washing soda.
Scouring agentsScouring, combing and/or carding our own fleece is time-consuming and fairly labour-intensive. I have tried scouring with the following scouring agents:
- Soap flakes
- Liquid soap
Caustic works by saponifying the lanolin on the fleece. This means that it turns the lanolin to soap which can then be rinsed away. I used the caustic on some Soay fleeces which are very soft, have no crimp and a short staple. Lanolin melts so the caustic can turn it into soap at temperatures above 38-40℃. Please note that the “soap” resulting from the saponification process is highly alkaline and will burn your skin if used. It becomes useable as soap only after at least six weeks or more.
In my experience, the fleece becomes rather hard and the tips become discooured and brittle and break off when caustic is used as the scouring agent.
Soap, whether flakes or in liquid form, emulsifies the melted lanolin. That is, the lanolin forms little globules that can be rinsed away. However, soap is generally remains alkaline and this will have an effect on the colour obtained from vegetable dyes. For this reason, I use liquid soap only on my dark fleeces that I am certain not to want to dye later on.
Detergents also emulsify the lanolin. There is an Australian detergent-based scouring agent called Fibre Scour which is effective but, in my experience, very expensive. The alternative which I use on fleeces that might be dyed is called Power Scour and seems to be much more economical. Both are pH-neutral (neither alkaline nore acidic) and will not affect the clours obtained from natural dyes.