A slub is a soft, thickened place in a yarn where the fibres bunch together, alternating with thinner sections along the yarn's length. Woven or knitted into fabric, slubs create a subtly irregular, streaked texture. Slubs began as a spinning fault to be eliminated; today they are engineered on purpose — slub yarns give linen-look cloth, textured T-shirt jersey, and the famous surface of dupioni and shantung silks, where the slub comes from double-cocoon thread.
How Slubs Are Made
A slub forms when the drafting (drawing-out) of fibres during spinning varies, letting extra fibre mass into the yarn at intervals. Modern mills control the pattern precisely: spinning frames are programmed to insert slubs of set length and thickness, randomly or in repeats, so a whole fabric can be textured evenly. In silk, the slub is natural — tangled double-cocoon filaments cannot be reeled evenly, and the thick places are inherent to the yarn.
Slubs run in the direction of the yarn that carries them. In slub jersey the streaks usually run horizontally across a T-shirt; in slubbed woven shirting they may appear in warp or weft. Because the thick places are less tightly twisted, they are slightly weaker and more absorbent than the thin sections — one reason slub fabrics dye with a pleasing, uneven depth.
Where Slub Effects Are Used
- Slub jersey T-shirts and tops — the biggest modern use; the texture upgrades a basic tee.
- Linen and linen-look fabrics — slubs imitate flax's natural irregularity in cotton and synthetic cloth.
- Silk dupioni and shantung — natural slubs define these classic fabrics.
- Denim and chambray — slub yarns add character and streaky fading to premium jeans.
Care of Slub Fabrics
Care follows the fibre, with one caution: slubs sit slightly proud of the surface and can snag or abrade faster than the ground. Wash inside out on gentle cycles, avoid rough zippers in the same load, and do not scrub at slubs when spot-cleaning. Slub textures relax slightly with washing, which most wearers welcome as a softer, more lived-in hand.
FAQs
- Is a slub a defect in fabric?
- Historically yes — slubs were spinning faults. Today most slubs are deliberately engineered texture, and fabrics are sold as 'slub' styles on purpose.
- What is slub jersey?
- Single-jersey knit made with slub yarns, usually cotton or cotton blends, giving T-shirts a streaky, textured surface instead of a flat one.
- Do slubs weaken fabric?
- Thick slub sections are a little less strong and more snag-prone than even yarn, but in well-made cloth the difference is a texture choice, not a durability problem.
Detailed Guides: see Slub in the glossary A–Z listing of the Apparel Search fashion glossary for related terms.