Walking gear for the Camino de Santiago – what is better: wool or man-made fibres?

Helly Hansen

Helly Hansen (Photo credit: Wikipedia)

In 2011, the writer discussed in three separate blogs walking gear and called them:

Good walking gear gives you a better walking outcome

Camino Downunder has not as yet discussed or given an opinion about the great on-going gear debate between  natural fibres i.e. wool and man-made woven yarns such as polypropylene,  polartec and technopile®. The writer appreciates all-woolen products, but will not hesitate, like David Ellis of Earth Sea and Sky, New Zealand to recommend the new man-made fibres such as, second generation polyesters.  David, with great lucidity and coherence clearly summarizes what the main issue is all about.  Earth Sea Sky‘s mission is high quality performance outdoor clothing.

Using superfine merino wool products when not undertaking heavy-duty physical activities is not a problem at all.  In the last ten years these products from such companies as Icebreaker have become very stylish and are practical and useful to wear all year round.  The writer is of the view that having tested at length in field tests “performance” of natural fibres (wool) and man-made yarns (polartec and similar), is of the opinion that the latter are superior when undertaking long and sustained physical exertion.  This is not to say that man-made fibres are superior in all areas.  It is simply to say that on balance and prioritising core functionality (wearing man-made fibres when doing very strenuous physical activities), the argument favours the non-natural fibres for “breathability” (wicking out perspiration), comfort next to the skin, ability to thoroughly clean and quickly dry when constantly on the move.

David Ellis established the performance outdoor clothing company Earth Sea Sky (ESS) in 1990. Prior to this he worked in the then family business Arthur Ellis & Co Ltd for 10 years where he was responsible for expanding the company’s range of Fairydown sleeping bags to include packs, tents and outdoor clothing.  ESS manufacture all their clothing in New Zealand and offer a full range of performance synthetic and natural superfine merino next-to-skin thermals.

In 2008, in his capacity as Managing Director of his company (Earth Sea Sky) David Ellis wrote a thoughtful, fair and well-balanced article about the evolving and high-performance outdoor fabrics and materials for people undertaking sustained and strenuous physical activities in the ‘great outdoors‘ (a Kiwi expression) and sometimes under extreme conditions.  His article appears below, unedited and unabridged and it sheds light and understanding about the differences and qualities between wool and man-made fibres.


Get Real – the true story of performance next-to-skin fabrics

In the mid 1970’s a quiet revolution occurred in the climbing community wardrobes throughout New Zealand. For those who can remember it was as though a weight had been removed, we traded our pink and cream Mosgiel woollens for the new brightly coloured, and often striped, revolutionary fibre called polypropylene. Mountaineers returning to New Zealand crammed their bags full of it, while those of us at home collected rationed postal notes to purchase it via international mail order. The conversion was fast and most of us had a couple of sets long before the local manufacturers started offering it. Such was the success of the switch the term “Polypro” became the generic slang for all thermals.

Polypropylene had been around for many years but it wasn’t until Italian researchers discovered how to spin it into yarn that it became relevant for clothing. Originally used as a liner in disposable nappies, it took the very clever visionary Helly Hansen in Norway to recognise the fibre had great potential for thermal underwear. The fabric kept the skin dry and warm by pushing the moisture away. It was ideal for Helly Hansen’s original market renowned for providing functional work wear for North Sea fishermen and ocean oil riggers. Unlike natural fibres, polypropylene kept the skin dry. Continually damp natural fibre, wool and cotton, waterlogged the skin. In sub-zero temperatures waterlogged skin became susceptible to frost bite. Polypropylene was so effective the incidence of frost bite on the North Sea became negligible overnight.

Since this time there has been a further advance in fabric technology. Polypropylene hailed from Europe but in the USA most textile manufacturers preferred using polyester yarn. Polypropylene is an incredibly strong yarn but it has a very coarse surface which is easily contaminated. This contamination does not wash free and after a period of time a permanent incrustation of body oils and odours around each fibre builds up, a bit like plaque on teeth. There are many old wives’ tales about how you should successfully clean your “Polypros” but unfortunately none of them work as the contamination is permanent. Badly contaminated polypropylene feels oily and in this state the very reason for wearing the fabric, to wick moisture off the skin, no longer works.

Polyester in comparison is a softer, smoother yarn. The smooth surface ensures anything that comes into contact with it during use will wash clean. By engineering the fabric yarns, 2nd generation polyesters from 1985 not only emulated but surpassed polypropylene’s functional properties. In a nutshell, superior performance without the odour build up.

Second generation polyesters use a permanent chemical treatment to maximise their moisture transferring and odour free properties. They can also use a mixture of yarn types or a mixture of yarn sizes to alter the surface to assist in this process. The treatment essentially changes the surface of the polyester from hydrophobic, water hating, to hydrophilic, water-loving. This changes the surface tension so water and perspiration is transferred outwardly and dries quickly. The same chemical treatment polishes the surface making it even more stain and odour free.

By using a mixture of yarns in the fabric construction (bi-component) the process of wicking, moisture spreading and drying can be further enhanced. These fabrics normally use a faster wicking filament yarn next to the skin and then a softer spun yarn on the outside which first stores then disperses (spreads) the moisture. Spreading is an important drying factor as a droplet of water falling against a t-shirt can dry three times faster if the fabric spreads the water over three times the original surface area.

By wicking the moisture through to the outer spun yarn, the filament yarn in contact with the skin dries very quickly. Although the outer surface will feel quite damp and will remain so until the heat from the body eventually dries it off, the inside surface is dry. Dry fibres insulate better than damp ones as moisture raids heat through conduction. It takes very little moisture content to significantly decrease the heat value of an insulation material. A 10% moisture content can halve the insulation ability of a fabric or filling. Warming up moisture in wet insulation takes a lot of body heat – the wet down sleeping bag effect. Effectively you have to warm up the moisture before the insulation material can bounce heat back to you. In most situations wet insulation is a net raider of body heat not a net provider. Ironically, when you are in a hypothermic situation your body metabolism starts slowing so your ability to warm up wet insulation is also vastly reduced. This can lead to disastrous results very quickly.

Synthetic fibres will only absorb between 1 – 3% of their weight in moisture. If a wet synthetic garment is hung up the water will “drop out” of the fabric very quickly. In the outdoors the final pooling area for dampness is easily removed by flicking dry this area.  This is quite different to the natural fibres where moisture absorption rates are well above 15%. Greater absorption leads to longer drying times with very little water “drop out” when the wet garment is hung up to dry.

It is near impossible to construct a laboratory test to simulate all of the variables that one experiences while wearing thermals in the natural environment.  For this reason laboratory data is very dangerous as numbers can easily be transformed to tell a myriad of different stories. Be very wary of comparable graphs and marketing claims. In the end it is wearer comfort in the field that is the most important consideration. I was recently asked by a very large marketer of fabric when discussing the performance of moisture management in treated polyester, “Did I have any scientific proof of what I was saying” By asking the question the marketer showed they had very little understanding of thermal insulation in the outdoors. Common sense needs to prevail and I would suggest all outdoor enthusiasts should experiment for themselves with what best suits their requirements for the activities and level of exercise they pursue.

In terms of odour all synthetic fabrics will smell, essentially they will smell as much as their wearer. They are all solid fibres and as such can only store body odour particles on their outside surface. The main difference between polypropylene and treated polyester is  polyester washes clean after each wear, polypropylene doesn’t. When you wear polypropylene you immediately get a combined body odour of all the previous wears.

© David Ellis  September 2008

Polypropylene still has its place in the outdoors. As an entry-level thermal it is still the best value insulation you can obtain. Treated polyesters are more expensive but in terms of value for money they will not only out-perform but they will also out-wear their well known rivals.

Natural fibres do not have wicking, moisture transferring or fast drying properties. Despite all the marketing descriptions these terms firmly belong to the synthetic fabrics.

So we now go back to where we started over 30 years ago. Was the passion and zeal to replace our woollen underwear incorrect or unfounded? I would suggest not as the very reasons why we did it then are equally relevant today.

David Ellis

Managing Director

Earth Sea Sky

©March 2008


An example of a man-made fibre from

  • soft next to the skin
  • insulation value
  • abrasion resistance
  • piling resistance
  • warm & light
  • easy care
  • breathable – moisture transferring
  • stretch
  • fast drying




  1. Amazing! Its genuinely remarkable article, I have got much clear idea
    about from this article.

  2. I must say I much prefer the man made shirts, over all they have lasted better and in the heat kept me cooler.

    • Evidence based testing clearly indicates that man-made fabrics outperform and outlast by a very long mile, pure woolen fabrics. And most importantly, they manage expelling moisture much more effectively from the body to the environment than natural fibers.

  3. Annette Roessle says:

    I did the Camino without a blister in my much loved bamboo socks. They were absolutely awesome I also supported my foot soles with walking wool and it worked for me.

  4. Can I just say what a comfort to discover a person who really understands
    what they are talking about on the net. You actually realize how to bring an issue to light and make
    it important. A lot more people need to check this out and understand this side
    of the story. It’s surprising you’re not more popular given that you most certainly possess the gift.

  5. Quality posts is the crucial element to attracting people to go to see the website, that’s what this site is providing.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: