Which Base Layer?

How to Choose Your Baselayer

Your baselayer is the foundation part of your layering system which is generally a 3 or 4 layers from the skin to the outside layer.  You "layer" in accordance with the conditions you are facing.

So what is a baselayer first of all?  Well it's your first "Next to Skin" layer which you may wear over underwear or may choose to wear "as" your underwear....that is a question of choice really. So your Baselayer is then followed by a mid-layer and sometimes a second mid-layer or Gilet perhaps, and finally a shell layer on the outside. The job of the baselayers is principally to regulate your temperature whether you're working hard or are more passive. It's an essential part of your layering system that shouldn't be overlooked and is going to make you feel the most comfortable for the activity you are undertaking.

How It Works

Particularly when you are very energetic, your body produces sweat. The harder you work, the more sweat you produce.....it's completely natural and also essential to life. Sweat then evaporates from your skin. That process of evaporation is what cools your body down.

When it's hot you need fewer layers, however, when it's cold in the middle of winter you will still sweat just as much as you would on a summer's day so cooling the skin is not ideal in that scenario. So this is where you would have a good layering system in play and your baselayer would be regulating your temperature by controlling the movement of sweat away from your body without the cooling effect - this process is called wicking. Baselayer fabrics draw the sweat away from your skin keeping your skin dry and in effect, bluffing your body into believing that it's "comfortable" and doesn't require the cooling effect of evaporation and therefore maintains your body temperature at the optimal level.

There are lots of different types of baselayers, but we're going to focus on the three main fabrics and look at the pros and cons of each.

1.       100% Merino Wool

High quality merino wool (no....not all Merino is high quality or ethically produced either) such as the Oasis Crewe from Icebreaker, dispel all the myths about wool being itchy - it is incredibly comfortable next to skin. This is because merino wool fibres are incredibly fine. The beauty of Merino Wool is that it has the natural ability to inhibit the build-up of odour because of natural keratin and lanolin both of which keep bacteria away that can cause fabric odours.

This means you can often wear merino wool baselayers for days on end and they usually won't smell which is fantastic for a ski trip, multi-day trekking or walking.  They wash relatively easily - they do, however, take a little bit longer to dry than a synthetic baselayer.

The downside to merino wool is that the natural fibres aren't quite as durable as synthetic fibres. Also, due to its premium quality (quality merino comes from genuinely mountain bred sheep) Merino Wool does come in at the higher end of the price bracket. However, it's not a huge difference if you consider that you may only need one top for a trip rather then two or three.

Pros to Merino

• Non-itchy due to the premium quality
• Odour-control
• Comfortable
• Moisture-wicking

Cons to Merino

• Takes longer to dry than synthetic
• Not best suited for fast-paced activities e.g. running, mountain biking
• More Expensive

2.       Synthetic Fabrics

Synthetic fabrics such as ODLO Performance Blackcomb or their Futureskin ranges, come into their own during high energy aerobic type activities where you're likely to sweat heavily. The big advantage of synthetic fibres is that they wick sweat away exceptionally quickly and they dry far quicker than Merino Wool.

They do tend to be a closer fit than 100% merino wool garments because they contain Elastane or Lycra which offers considerable stretch but they're not restrictive and still fit exceptionally comfortably.

The weight of the fabric will determine its insulating properties; ideally what you want is a thin layer that's regulating your temperature and pulling any moisture away from your body. Another big plus is that they wash incredibly easily at 30 degree and you're good to go the next day!

There are a couple of downsides - Synthetic fibres don't have the same odour-controlling properties that merino wool has. This means that you'll probably need two or three tops if you're off for a longer trip. Some manufacturers are working odour-controlling technologies, like ODLO's Effect which uses Silver Ions into their garments but even so, the nature of the fabric means that they can still attract bacteria and will need washing more frequently than merino.

Pros of Synthetics:

• Comfortable
• Rapid moisture wicking
• Quick drying
• Easy to wash
• Generally cheaper then Merino wool
• More durable than Merino Wool

Cons of Synthetics:

• No natural odour controlling properties
• Will need washing more regularly than Merino Wool

3.       Synthetic/Merino Wool Blend

Synthetic and Merino wool blend garments could be considered as the utopia of the sector in that they offer the best of both worlds.  The Helly Hansen Lifa Warm or the Floa Backcountry blended fabrics are just about perfect for any winter adventure.

The merino wool fibres are wrapped around the synthetic fibres so you get the benefits of both; the durability, the quick drying, the high wicking properties of the synthetic fibres teamed with the comfort, softness, odour control and the consistent temperature regulation of merino wool.

They sit snug like the synthetic garments because you need that close fit for the synthetic fibres to work more effectively. They still wash very easily too at just 30 degrees.

The only real down-side is that 100% synthetic garments still wick moisture away faster during high output sports like running and mountain biking. The fabric blend is also harder to make meaning the garments are usually more expensive than 100% synthetic or merino wool products.

Pros to Synthetic/Merino Blend

• Combines the benefit of both fabrics
• Quick drying
• Good odour control
• Durable
• Soft
• Comfortable

Cons to Synthetic/Merino Blend

• More expensive than Merino and Synthetic garments
• Not as suited to high-output activities than 100% synthetic garments