How to Scour

Our How To guides are intended to make the dye process easy for our customers, from scouring and mordanting your fibers to dyeing with an assortment of dyes. You can find other How To guides here.

What is Scouring?

“Scouring” is the textile term for cleaning fibers and removing sediment prior to mordanting and dyeing, and does not refer to washing fabrics in a washing machine. If the fiber is not clean, the mordant and dyes will not adhere well to the fiber. Fabrics sold as gray goods or “greige” require a thorough scour. Fibers need scouring if they feel greasy (ex. wool fleece), are smelly or are visibly dirty. Even products that are sold as Ready for Dyeing (RFD) or Prepared for Dyeing (PFD) often need a light scour prior to use. The scouring methods for animal fibers, cellulose fibers and silk are all different. Scouring ingredients are commonly a neutral soap such as Eucalan, Orvus Paste or a neutral laundry soap, Cellulose Scour, and Soda Ash. Sometimes white vinegar is used to neutralize scour effects on protein fibers. Check out our recent Q & A: Round Up of Mordanting + Scouring 101 here.

Scouring Animal Fibers (Sheep, Alpaca, Goat)

You can scour animal or protein fibers with a wool detergent like Eucalan, or use a household liquid dish soap such as Dawn. You could also use a pH neutral, unscented laundry detergent such as Tide, or a soap such as Orvus Paste. Dawn and Tide make a lot of suds, and Orvus and Eucalan are low sudsing.  All clean animal fibers well. When scouring, note that all fibers should be pre-wet with tap water so absorption is even.

Calculating the Amount of Scour

To calculate the amount of scour needed, you must first calculate the Weight of Fiber or WOF. This refers to the dry weight of the yarn or fiber to be scoured, which then allows you to quickly calculate how much detergent you need. A kitchen scale is handy to determine the weight of yarn or fabrics. For commercially prepared yarns, use 0.5-1% WOF. For example, for 100 grams of commercially prepared yarn, you would use 1 gram of detergent. For raw wool or organically processed yarns, use 1-3% WOF. If your wool or yarn feels exceptionally greasy or dirty, use up to 5% WOF.

You will need

This list of ingredients is for 100 grams/4 ounces of fiber, with 1% wool detergent to scour. Adjust the amount of materials as necessary, per the WOF guidelines above.

• • 100 grams/4 ounces fiber

• • 1 gram Eucalan (if fibers are heavily soiled, like raw wool in the grease, use up to 5% WOF or 5 grams)

• • A container for dissolving detergent

• • A large stainless steel dye pot, large enough to hold your fibers with plenty of room to move around

• • Heat source

Instructions

Remove fibers from the dye pot (be careful as they are very hot) and rinse them in water that is the same temperature to avoid felting them with a sudden temperature shift. You may allow the fibers to cool slightly for safe handling. You may need to rinse fibers twice. Handle gently to avoid felting and tangling. If your scour water is dark colored, you should repeat the scouring process again. Once your fibers are rinsed, gently squeeze out excess water and proceed to mordanting. You can leave fibers overnight in rinse water, or in a plastic bag if you are going to mordant soon. You may store scoured fabrics once they are dry until you are ready to mordant. For longer term storage, air dry the fabric once you are completed scouring or mordanting. I like to store them in cloth or paper bags with a tag attached to the fiber with a date and a label that tells me if it’s scoured and/or mordanted, and what type of mordant. It saves me a lot of time when I’m digging around looking for something to impulse dye.

Scouring Cellulose (Plant) Fibers: Two Methods

Scouring is different than washing fabrics, and if you are scouring, you do not need to pre-wash the fibers. All fibers should be pre-wet so absorption is even.

Calculating the Amount of Scour

To calculate the amount of scour needed, you must first calculate the Weight of Fiber or WOF. This refers to the dry weight of the yarn or fiber to be scoured, which then allows you to quickly calculate how much detergent you need. A kitchen scale is handy to determine the weight of yarn or fabrics.

Method One: Cellulose Scour and Soda Ash

Cellulose scour helps break the surface tension of the fibers similar to detergents such as Synthrapol. Cellulose scour: the recommended amount of cellulose scour liquid is 5.5% of the WOF, or approximately 1 teaspoon for 100 grams of fiber. Soda ash: the recommended amount of soda ash is 1-2% of the WOF, or approximately 1/4 – 1/2 teaspoon for 100 grams or 4 ounces of fiber. If your fabric feels particularly dirty or greasy, use 2% WOF.

You will need

This list of ingredients is for 100 grams/4 ounces of fiber. Adjust the amount of materials as necessary, per the percentage guidelines above.

• • 100 grams/4 ounces fiber

• • 5.5 grams/.2 ounces/1 teaspoon cellulose scour

• • 2 grams/.3 ounces/1/2 teaspoon soda ash

• • A container to dissolve the soda ash

• • A large stainless steel dye pot, large enough to hold your fibers with plenty of room to move around

• • Heat source

Instructions

Method Two: Soda Ash

This method is an easy-to-remember formula. Soda ash: the recommended amount of soda ash is 1-2% of the WOF, or approximately 1/4 – 1/2 teaspoon for 100 grams or 4 ounces of fiber. If your fabric is unbleached or feels particularly dirty or greasy, use 2% WOF.

You will need

This list of ingredients is for 100 grams/4 ounces of fiber. Adjust the amount of materials as necessary, per the percentage guidelines above.

• • 100 grams/4 ounces fiber

• • 2 grams/.3 ounces/1/2 teaspoon soda ash

• • A container to dissolve the soda ash

• • A large stainless steel dye pot, large enough to hold your fibers with plenty of room to move around

• • Heat source

Instructions

Wet out the soda ash first with a little cold water, and then gradually add boiling water to dissolve. Fill a dye pot with enough room temperature water so the fibers move easily and place on a heating source. Add the dissolved soda ash to the dye pot. Stir well. Add the wet fiber to the dye pot and slowly bring the temperature to 180°F, rotating the fibers gently. Hold at 180°F for 30 minutes. Remove fibers from the dye pot (be careful as it is very hot), rinse in cool water, extract excess water and proceed to mordanting. If the fibers are particularly dirty, you may repeat the process.

Scouring Silk Fibers

Silk yarn and yardage is generally sold already well scoured; if it is very soft and white, then the sticky protein called sericin has already been removed. However, if you are working with silk noil, raw tussah yardage or silk yarns that feel stiff and wiry, then scouring them will help improve color results and quality in the dyed goods.

Calculating the Amount of Scour

To calculate the amount of scour needed, you must first calculate the Weight of Fiber or WOF. This refers to the dry weight of the yarn or fiber to be scoured, which then allows you to quickly calculate how much detergent you need. A kitchen scale is handy to determine the weight of fiber. Detergent: Use 0.5-1% WOF of neutral detergent (such as Eucalan, Orvus or Dr. Bronner’s) Soda Ash: Use 1%-5% WOF of soda ash per 100 grams or 4 ounces of fiber. Note: use caution when working with very stiff silk as the higher percentages of soda ash can damage fibers. When in doubt, test first. Vinegar: Use 5% WOF of white vinegar to neutralize the fibers after scouring.

You will need

This list of ingredients is for 100 grams/4 ounces of fiber. Adjust the amount of materials as necessary, per the percentage guidelines above.

• • 100 grams or 4 ounces of silk fiber

• • 1 gram of neutral detergent

• • 1/4 teaspoon or 1 gram of soda ash up to 1 1.4 teaspoons for very stiff and wiry silks.

• • Two small containers to dissolve the detergent and soda ash

• • A large stainless steel dye pot, large enough to hold your fibers with plenty of room to move around 

• • A large stainless spoon or tongs

• • Heat source

Instructions

Wet out the soda ash first with a little cold water, and then gradually add boiling water to dissolve. Dissolve the detergent in a small container. Fill a dye pot with enough room temperature water so the fibers move easily and place on a heating source. Add the detergent and soda ash and stir well. Add the wet fiber to the dye pot and slowly bring the temperature to 160-180°F, rotating the fibers gently. Hold at 160-180°F for 30 minutes. Remove fibers from the dye pot (be careful as they are very hot) and rinse in hot water. If your scour water is very dark, you may need to scour a second time to remove all of the impurities from the fibers. Once your rinse water is clear, add 5% WOF of white (distilled) vinegar to the rinse water and let the fiber soak in the vinegar water for 20 minutes. Remove, rinse in cool water, remove excess water, and proceed to mordanting.