Sourcing apparel in bulk is a capital-intensive decision. For sourcing managers and fashion startups, the biggest risk is inconsistency: receiving a shipment where the production units do not match the initial sample.

At Om Cotton, we often see buyers relying on visual aesthetics or vague terms like premium feel to make purchasing decisions. However, in manufacturing, quality is not a feeling; it is a measurable set of technical parameters.

This guide outlines the specific technical standards and testing protocols we use to assess cotton fabric quality. By understanding these metrics, from yarn composition to dimensional stability, buyers can distinguish between commercial-grade fabric and true export-quality manufacturing.

Importance of Fabric Quality Control in Bulk Sourcing

In the B2B apparel industry, the difference between a successful product line and dead inventory often lies in the fabric’s behavior after the purchase. High-quality manufacturing is defined by predictability.

When we discuss “Export Quality” versus “Market Quality,” we are referring to the strictness of the tolerance levels.

  • Market Quality: Often relies on carded cotton, accepts higher shrinkage rates (up to 7-8%), and uses lower-grade dyes.
  • Export Quality (Om Cottons Standard): Utilizes combed/ring-spun cotton, maintains shrinkage below 5%, and ensures high color fastness.

Without a defined quality control (QC) process, bulk buyers risk issues like torquing (side-seam twisting), excessive pilling, and shade variation between batches.

GSM vs. Thread Count: Selecting the Right Metric

One of the most common misconceptions among new buyers is the application of “Thread Count” to knitwear.

  • Thread Count: This is a metric for woven fabrics (bed sheets, dress shirts). It measures the number of threads per square inch.
  • GSM (Grams per Square Meter): This is the metric for knitted fabrics (T-shirts, Hoodies, Sweatshirts). It measures the weight and density of the fabric.

For bulk apparel, GSM is the primary indicator of thickness and drape, but it does not guarantee durability on its own. A high GSM fabric made from weak yarn will simply be heavy and brittle.

Standard GSM Ranges for Cotton Apparel:

  • Lightweight T-Shirts: 140 – 160 GSM
  • Standard/Heavy T-Shirts: 180 – 220 GSM
  • Polo Shirts: 200 – 240 GSM
  • Hoodies & Sweatshirts: 300 – 450 GSM

Note: For items like the Ski Mask Hoodie mentioned in market trends, a minimum of 350 GSM is recommended to ensure the hood maintains structure and provides adequate thermal retention.

Yarn Quality: Combed, Carded, and Ring-Spun Cotton

The durability of the fabric is determined by the yarn spinning process. At Om Cotton, we prioritize yarn strength and surface smoothness. Buyers should specifically request the following yarn types in their “Tech Pack.”

Combed vs. Carded Cotton

  • Carded Cotton: The raw cotton is cleaned and aligned, but short fibers remain. This results in a fuzzier texture. Carded cotton is cheaper but prone to pilling (formation of small fabric balls) after washing.
  • Combed Cotton: The cotton undergoes an extra combing process to remove short fibers and impurities. This leaves only long, straight fibers.

Result: Combed cotton is softer, stronger, and significantly more resistant to pilling. For premium branding, we strictly recommend combed cotton.

Ring-Spun vs. Open-End

  • Open-End (OE) Spinning: A faster, cheaper method. It creates a yarn that is bulky and has a crisp or rough hand feel.
  • Ring-Spun: The yarn is continuously twisted and thinned. This creates a tighter, finer, and stronger yarn rope.

Result: Ring-spun fabric has a smoother surface, which is critical for DTG (Direct to Garment) and Screen Printing. The ink sits evenly on ring-spun fabric, whereas it can look grainy on open-end fabric.

Fabric Testing Standards: Shrinkage and Color Fastness

Before fabric is cut and sewn, it must undergo physical testing. We encourage buyers to ask manufacturers for a Lab Dip Report or a Fabric Test Report.

Dimensional Stability (Shrinkage)

Cotton is a natural fiber and will shrink. The goal of quality manufacturing is to control this shrinkage through compacting processes.

  • The Test: We mark a specific area on the fabric, wash it according to care instructions, and measure the change.
  • The Standard: Acceptable shrinkage for knit cotton is +/- 5%. Anything higher indicates that the fabric was not properly relaxed or compacted during finishing.
  • The Consequence: If a zipper hoodie shrinks 8% vertically, the zipper (which does not shrink) will buckle and wave. This is a clear sign of poor manufacturing.

Color Fastness

This measures how well the fabric retains dye when exposed to external agents.

  • Fastness to Washing: Does the color bleed onto other clothes?
  • Fastness to Rubbing (Crocking): Does the dye transfer when rubbed against a white surface (dry and wet)?
  • Fastness to Light: Does the color fade under sunlight?

We evaluate this on a Gray Scale of 1 to 5, where 5 is excellent (no change) and 1 is poor (severe fading). Export quality typically demands a minimum rating of 3-4.

Spirality (Torquing)

Have you ever worn a t-shirt where the side seam twists around to your stomach after a wash? This is called Spirality. It occurs when the tension in the knitted yarn is not balanced. High-quality manufacturing tests for spirality to ensure seams remain straight.

Stitch Density and Knitting Structure

Once the fabric passes quality checks, the assembly process begins. The durability of the final product depends on stitch quality.

SPI (Stitches Per Inch)

This measures the density of the sewing.

  • Low SPI (8-10): Faster to produce, uses less thread, but creates weak seams that can gap open under stress.
  • High SPI (12-14): Slower production, but creates a tight, durable seam. For heavy items like hoodies and pants, a higher SPI is non-negotiable to prevent seam failure.

Ribbing Recovery

For cuffs and waistbands, we use a cotton-spandex blend (often with 3-5% Lycra/Elastane).

  • The Test: Stretch the cuff to its maximum width and release it.
  • The Standard: It should snap back to its original width immediately. If the ribbing remains loose or wavy, the elastane quality is poor, and the garment will look old after a few wears.

The Role of GOTS Certification in Quality Assurance

For buyers specifically sourcing Organic Cotton, visual inspection is insufficient. Conventional cotton and organic cotton look identical to the naked eye.

GOTS (Global Organic Textile Standard) is the leading processing standard for textiles made from organic fibers. It verifies:

  1. Fiber Integrity: The cotton is truly organic (no GMOs).
  2. Chemical Safety: No toxic heavy metals, formaldehyde, or aromatic solvents are used in processing.
  3. Traceability: We can trace the transaction certificate (TC) from the farm to the final garment.

As a manufacturer, Om Cotton provides GOTS Transaction Certificates to prove that the “Organic” label on your product is backed by a verified supply chain.

Verifying Your Manufacturer’s Specifications

Quality assessment is not about guessing, it is about verifying specifications. When approaching a manufacturer for bulk orders, do not just ask for a sample. Ask for the Technical Specifications:

  1. What is the exact GSM?
  2. Is the yarn Combed and Ring-Spun?
  3. What is the shrinkage tolerance?
  4. Can you provide a GOTS certificate?

At Om Cotton, we believe transparency is the foundation of a long-term manufacturing partnership.

Bonus for Buyers

If you are planning a bulk order and want to verify the difference between standard market fabric and export-quality organic cotton, we invite you to request our Fabric Quality Swatch Kit.

This kit includes samples of various GSM weights, combed vs. carded comparisons, and finished ribbing samples so you can perform these assessments yourself.

By Amrita SharmaQuality & Control