Why hoodies are fleecy inside

Short answer: Because the back of the fabric is brushed with fine needles, so the loops open up and form a soft surface. It is a treatment, not a property of the fibre. That is why the same yarn can become smooth or fleecy sweat, depending on how the fabric is finished.

How the fleecy back is made

Sweat fabric is knitted, so the back consists of small loops. The fabric runs over rollers with small hooks that pull the fibres out of the loops and raise them. The result is a soft, airy surface against the skin that feels quite different from the front. See the styles in bamboo hoodie for men.

Why it keeps you warm

The raised fibres hold on to air, and air is what insulates. That is why a brushed fabric feels warmer than a smooth one of the same weight. You get more warmth without the fabric having to be thicker or heavier, which suits cold days. See the range in bamboo sweat for men and women.

The fleece flattens over time

After many washes the fibres lie down and the fabric becomes less fleecy. It happens gradually and is not a fault, just part of clothes being worn. It cannot be brought back once the fibres have settled. The fabric stays soft but holds a little less air. See the styles in bamboo sweatshirt for women.

A treatment, not a property of the fibre

The fleecy side does not depend on what the yarn is made of. Brushing creates it. The same fabric can therefore be made with or without a fleecy back. That is worth knowing when you choose, because it is the treatment and not only the material that decides how warm and soft a hoodie feels inside.

Brushed or unbrushed

Unbrushed sweat keeps the small loops on the back. It is thinner and cooler and is often worn in spring and autumn, or by anyone who gets warm quickly. Brushed sweat is the obvious choice for winter and cold days at home. With both types in your wardrobe, you can switch with the season.

Loose fibres and pilling

Because the fibres are raised, some can come loose and gather into small balls, especially where the fabric rubs, such as under the arms. That is normal and does not mean the fabric is poor. A fabric shaver removes them easily. Move it gently over the fabric while it lies flat so you do not pull the fibres.

Lint in the first washes

A new hoodie with a fleecy back can shed a little lint the first few times it is washed. These are loose fibres from the brushing that have not settled. Wash it with clothes in similar colours so the lint does not show on other garments. Clean the machine filter regularly.

How to protect the fleecy side

Gentle washing and no tumble dryer slow down the flattening. Wash at 40 degrees with a low spin and let the hoodie dry flat. Skip fabric softener, which can make the fibres clump. Air it between wears instead of washing it every time. The fewer washes, the longer the back stays soft.

Frequently asked questions

Is there sweat without a fleecy back

Yes. Unbrushed sweat is thinner and cooler and is worn in spring and autumn. It also suits you well if you tend to get too warm indoors.

Does the fleecy side turn into pilling

Some loose fibres can gather into small balls. A fabric shaver removes them easily, and the rest of the fabric is not affected if you are gentle.

Can you stop it from flattening

Not completely. Gentle washing and no tumble dryer slow it down noticeably, and airing the hoodie instead of washing it every time also helps.