Base Layer Buying Guide

Sourced from the Merino sheep, Merino Wool is a great base layer material. Extremely warm, brilliantly breathable, and oh-so-soft and comfortable against your skin, merino wool base layers are a fantastic choice for cold and warm climates. Merino wool is also naturally anti-bacterial, resisting odour even after multiple wears without washing.

Some base layer manufacturers take a synthetic fibre and blend it with a natural fibre like merino wool. This process combines the beneficial qualities of both materials. The result is a hardwearing, quick-drying, breathable, and warm hybrid base layer. It is then possible to change the ratio of the blend until the quantities of each material are fine-tuned to suit a specific activity or climate.

One of the most important characteristics of a base layer is its ability to wick away moisture. Like the wick of an oil lamp, this process involves the fibres of the base layer pulling sweat away from your skin's surface before passing it along its length to move away onto the next layer of clothing or to be dispersed. This technology keeps your skin dry and at a regular, comfortable temperature.

As your base layer will sit directly against your skin, base layers are made from smooth fibres to generate very little friction. Many base layers utilise ‘flat-lock seams’ to give stitches a low profile to avoid scratching and itching. Some base layers also avoid having seams over the shoulders to minimise the friction from rucksack straps or under the flanks for additional comfort.

When working hard in warm conditions, a gentle through-flow of air is always appreciated. Zip necks are one way to customise the level of ventilation, as are thinner pieces of perforated material that cover the underarms or along the spine. Aerating features keep your temperate consistent, rather than getting hot and sweaty during activity and damp and chilled when stationary.

Breathability is different to ventilation, referring to the ability of a material to allow sweat vapour to pass through the fibres. If a material is not breathable, then every molecule of water vapour expelled from your skin would be trapped, like condensation against a window. Synthetic materials are very good at breathing efficiently, absorbing little water and drying quickly.

Base layers are made in a variety of densities and thicknesses. Generally speaking the colder the conditions the warmer and thicker you will need the layer. However, the type of activity you're undertaking is also fundamental to this requirement. If you're working hard in the extreme cold, we suggest using a thinner layer than if you are stationary in milder conditions.

Base layers are like a stretchy second skin - and like your skin - they should follow the contours of your body and move with you through a range of actions. You don't want your base layer to be too baggy or feel too restrictive: If it is too tight, the seams will rub, causing fibres to rip open. Too baggy, and all that warm air will easily escape.

Although base layers for the torso are the most common, the materials used and the theory involved are the same all over the body. For example, legs work hard and take up a large surface area, so base layer trousers and pants ensure they stay warm, dry and comfortable. In addition, gloves, headwear, and thermal pants can all keep you cool, comfortable, and your temperature regulated - so you can enjoy the comfort of a base layer everywhere.