What is fleece?

Fleece, no doubt you have heard of it. Chances are you even have one or more cardigans of it hanging in your closet. But what exactly is it? And why is it used so much by campers, trekkers, winter sports enthusiasts and climbers? We discuss it in this blog.

Table of contents

• The origins of fleece
• What makes fleece so popular?
• Fleece types
• Warmth vs. weight
• Fleece and the environment

The origins of fleece

Fleece is a man-made material designed to mimic the pleasant properties of wool. In the late 1970s, textile company Malden Mills (known as Polartec, the current market leader in fleece after a bankruptcy in 2007) experimented with the use of synthetic fabrics. In 1981, the company introduced fleece to the market, thanks to a collaboration with Yvon Chouinard, owner of the then unknown Patagonia. This first generation fleece was called Synchilla and within a decade it was widely used in sports and outdoor clothing. It completely changed the way we dress for outdoor activities.

As mentioned, fleece is a synthetic fabric, usually made from a type of polyester called polyethylene terephthalate (PET). The polyester fibres are woven into a lightweight fabric, which is then brushed to give the fibres more volume. Sometimes other natural fibres are incorporated into the fleece fabric, such as wool, hemp or viscose to add a certain texture or vibrancy to the fabric. Nowadays, fleece is also made from recycled plastic, such as PET bottles. The latter type of fleece is often called ECO fleece.

What makes fleece so popular?

We see fleece in the outdoor world mainly in the form of fleece vests, but sometimes also in hats and headbands or as a lining in jackets. As a fleece vest, it is an excellent choice as an insulating mid-layer in the 3-layer system. Why? First of all, fleece retains your body heat well. So it insulates very well. Secondly, the price of fleece is attractive. Wool is generally more expensive and this applies even more to down-filled insulating jackets. Fleece is also hydrophobic. This means that it does not absorb water. It therefore dries very quickly. Faster than wool. However, fleece is not wind- and waterproof,which also makes it unsuitable for the outer layer within the 3-layer system. It also insulates less than wool once wet. Fleece fabrics, on the other hand, are fairly easy to maintain. It is not odour neutralising, but it is easier (and less restrictive) to wash than wool, for example. Finally, fleece is also highly comfortable to wear. It is warm, lightweight, feels comfortable on the skin and has excellent breathability.

Fleece jackets fit perfectly within the 3-layer system, making them a very good choice as a midlayer for activities such as hiking, winter sports or climbing. However, for activities in a very cold environment, the insulating jacket may be a better choice as a midlayer. Indeed, this type of jacket can offer more warmth. Finally, thanks to the combination of an attractive price and high wearing comfort, fleece is also a very popular option for camping or other more casual activities.

Fleece types

Fleece was once designed to mimic the skin and wool of a sheep. As a result, the original variants have a high-pile exterior and a smooth interior. But because fleece is completely synthetic and different wishes have been expressed from the market over the years, a lot of different fleece types have been developed. Some types focus more on optimal comfort, while others concentrate more on technical specifications such as the lowest possible weight. It would go too far to discuss all existing types, but we can briefly go over some common ones.

Polar fleece: this is the most traditional type of fleece. It contains few technical gadgets, but all the valued properties of fleece. It is also produced using standard weaving methods.

Micro fleece: is the thin version of polar fleece.

Knit fleece: a type of fleece fabric characterised by its knitted construction. Unlike the above fleeces that are woven, knit fleece is knitted using a special knitting technique. This results in a warm fabric that looks good and is less prone to fluffing. This fleece variant is a lot heavier than the fleeces above, though.

Grid fleece: this is a type of fleece fabric characterised by a grid pattern on its surface. This grid pattern is created by the way the fabric is knitted or woven. The fabric has a waffle-like structure with small square or rectangular openings. The result is a very breathable fleece fabric, which is also lightweight and has a low pack volume.

Sherpa fleece: a type of fleece fabric known for its warmth and softness. It has a fluffy texture that resembles the fur of a sherpa, hence the name. This fleece is often made of polyester and has a smooth finish on one side, while the other side has a woolly, fluffy surface. This type of fleece is used in the more casual fleece vests.

Warmth vs. weight

To get an idea of how warm a particular fleece is, it is best to look at the sometimes available fleece specifications: fabric thickness or fleece weight. This is often expressed in grams per square metre, such as 100, 200 or 300 g/m2. In its lightest form (around 100 g/m2), a fleece is only slightly warmer than thermal clothing in terms of insulation. Ideal for the warmer days of the year or for very strenuous activities. Medium category fleeces (around 200 g/m2) are warmer and are a very good option for autumn and spring or for days with mild weather on the slopes. Heavy fleeces (around 300 g/m2) are warm and insulate in sub-zero temperatures, but their size often comes at the expense of breathability and elasticity/flexibility. Unfortunately, far from all brands are very clear in what the fabric thickness or weight of the fleece they use is. So it is not always easy to make a choice on that basis.

Fleece and the environment

Is fleece also a sustainable and ethical choice? At least for the production of fleece, there is no need to use materials from animals (such as down or wool), making it 100% vegan. In addition, fleece is increasingly made entirely from recycled materials, but this is where the plus points end. After all, fleece remains a synthetic material based on petroleum. In addition, unlike cotton or down, fleece production emits greenhouse gases. Fleece also wears out (slowly) when worn or washed, releasing microplastics into nature. Multiple studies have shown, that with every wash of one fleece vest, thousands of fibres are released into wastewater. These fibres eventually end up in the oceans.

What can you do about this? First of all, choose fleece made of recycled polyester. Fortunately, this is increasingly the case with almost all fleece vests you find in our range. Also, choose high-quality fleece clothing as much as possible. High-quality fleece wears out significantly less quickly and therefore releases fewer microplastics. Finally, you can also try to minimise the number of washes of your fleece clothing. Often, airing your fleece outdoors is enough to quickly freshen it up.

Hopefully, in this blog we have been able to explain to you exactly what fleece is and why it is so widely used in the outdoor world. Have we also convinced you of the added value of fleece? If you still have any questions or would like to benefit from our expertise, do not hesitate to contact our customer service team. Of course, you can always visit our shop in Groningen.