How Factories Fight Shrinkage: A Behind-the-Scenes Look at Knitwear Finishing

Shrinkage is one of the most common concerns in knitwear—whether you're a retailer, a designer, or a consumer. That moment when a beloved jumper emerges from the wash a size smaller is more than just frustrating; it’s a challenge to brand trust and product longevity. But what many don’t see is the meticulous work that goes on behind the scenes to prevent it.

In this article, we’ll walk you through how factories tackle shrinkage head-on, the treatments involved, and why understanding these processes is key to making informed decisions in sourcing and product development.

What Causes Shrinkage in Knitwear?

Before we dive into the solutions, it’s worth understanding the problem. Shrinkage in knitwear typically stems from:

• Fibre type: Natural fibres like wool and cotton are more prone to dimensional changes when exposed to moisture, heat, and agitation.

• Yarn structure: Loosely spun yarns or open knit constructions can shift more easily.

• Finishing tension: Knitwear is often stretched during production and may relax post-wash.

• Washing conditions: High temperatures, aggressive detergents, and tumble drying accelerate shrinkage.

The Factory’s Toolkit: Anti-Shrinkage Treatments Explained

Factories employ a range of techniques to stabilise knitwear and reduce shrinkage risk. These treatments are applied during the finishing stage—after knitting and before packing.

1. Heat Setting

A controlled heat treatment that relaxes the fibres and locks the garment into its intended dimensions.

• Common for synthetic blends and some wool types.

• Helps stabilise shape and reduce post-wash distortion.

• Requires precise temperature control to avoid fibre damage.

2. Pre-Washing / Relaxation Washing

Garments are gently washed before shipping to allow natural shrinkage to occur in a controlled environment.

• Mimics consumer washing conditions.

• Allows the factory to measure and adjust sizing accordingly.

• Often paired with tumble drying or flat drying under tension.

3. Steam Finishing

Steam is used to relax fibres and reshape garments without aggressive mechanical action.

• Ideal for delicate knits and wool-rich blends.

• Helps restore garment dimensions after knitting and linking.

• Often used in combination with pressing or blocking.

4. Chemical Treatments

Specialised finishes can be applied to fibres to reduce shrinkage.

• Enzyme treatments for cotton to reduce fuzz and improve dimensional stability.

• Resin or polymer finishes for synthetics to lock in shape.

• Must be carefully balanced to avoid affecting hand feel or breathability.

Quality Control: Measuring Shrinkage Before It Reaches You

Factories don’t just treat garments—they test them. Shrinkage is measured using standardised wash tests, often based on ISO or AATCC protocols. Key steps include:

• Pre-wash and post-wash measurements of length and width.

• Documentation of shrinkage percentages per style and batch.

• Adjustments to pattern specs to compensate for expected shrinkage.

This data is crucial for brands and buyers—it ensures that the garment fits as intended after the first wash, not just when it’s fresh off the line.

Why This Matters to Buyers and Brands

Understanding anti-shrinkage treatments isn’t just technical trivia—it’s a strategic advantage. Here’s why:

• Better product performance: Garments that hold their shape build customer trust.

• Fewer returns and complaints: Shrinkage is a top reason for dissatisfaction.

• Clearer communication: Educating your customers on care and expectations strengthens your brand.

• Smarter sourcing: Knowing what treatments are available helps you ask the right questions and choose the right partners.

Shrinkage may be a natural behaviour of knitwear, but it’s far from uncontrollable. With the right finishing techniques, careful testing, and transparent communication, factories can deliver garments that perform beautifully wash after wash.

So next time you’re reviewing a tech pack or discussing production with your supplier, ask about their anti-shrinkage protocols. It’s not just about avoiding surprises—it’s about building quality from the inside out.