Complete guide to merino wool

Merino wool is a game-changer in outdoor wear. What makes Merino wool unique is also what makes it perfectly suited for base layers and any clothing that requires a full range of movement. In other words, Merino wool is a game-changer in outdoor wear as well as base layers.

Ask most people what the first woollen thing is they picture, and chances are they’ll say warm, woollen scarves, hats or gloves and possibly a chunky knit jumper. Merino wool challenges the stereotypes in many ways. 

Merino wool is named after the Merino breed of sheep that it comes from. Merino wool fibres are extremely fine. Despite their soft, fine wool Merino sheep are a large and resilient breed of sheep originating in Spain, due to the popularity and usefulness of their wool the Merino sheep breed has spread around the world. These days most Merino sheep are bred and raised in Australia and New Zealand.

Merino wool is one of the highest performing natural materials, but it’s imperative to know how to care for it. Read on to discover how Merino wool is made, how to compare 100% Merino to wool blends, what Merino wool is best for, and crucially how to care for Merino wool.

How Merino wool is made

Merino sheep are sheared once or twice a year from the Merino sheep breed after they’re thoroughly groomed and cleaned. Then even after the pre-shear cleaning, the wool fibres require further processing.

Cleaning the shorn wool starts by removing any residual dirt and debris, sometimes in a manual process done by wool handlers. After that further washing takes place to remove additional contaminants and a lot of the lanolin from the wool with hot water. Lanolin is the natural waterproofing and moisturising produced by sheep to protect their fleece from the environment.

Then the Merino wool is sorted and graded. The factors that wool sorters classify Merino wool fibres by include the: 

• Diameter

• Length

• Colour

100% Merino wool vs. Merino wool blends

A 100% Merino wool garment is considered the crème de la crème of wool clothing and accessories. There are also different blends of Merino wool with other fibres as well. When looking for a Merino wool garment to buy or for Merino wool knitting wool you’ll be able to select your garment or wool by looking at the percentage numbers designed to notify consumers how much of a garment is Merino, other wool or a synthetic blend. Some common blends with synthetics are: 

• 95% Merino, 5% synthetic 

• 65% Merino, 35% synthetic

• 50% Merino, 50% synthetic

Don’t underestimate the benefits of 100% Merino wool.  However, there are advantages to blending Merino wool with synthetic materials such as polyester or Lycra, or also with organic fibres such as cotton or bamboo. 

Polyester is a synthetic addition that is generally chosen to be used as a filler to offer added resistance or to offer a lower price than 100% Merino.  When you buy a Merino and polyester blend jumper it is likely that it can be treated with less care than a 100% Merino wool garment. With the trade-off being that less Merino wool means less of the natural antibacterial and odour-resistant qualities of wool. Therefore while the jumper with a wool and polyester blend might be easier to wash, conversely it will also require more frequent washing due to the reduction of antibacterial and odour resistance, meaning that it will wear considerably more over time than a full Merino or Merino wool blend product. 

Although wool has natural stretch, adding Lycra creates a wool blend article that offers even more stretch. Lycra also helps to give a garment shape as it creates clinging to the wearer when the size is right. 

Wool blended with cotton, in contrast, combines two natural fibres at the intersection of their benefits. Wool provides breathability and cotton allows for a tighter weave whilst bamboo, like wool has high sustainability credentials.

Ultimately, your choice of whether you purchase 100% Merino wool, a wool blend or a Merino-synthetic blend depends on your requirements for the garment and how you want to care for it. A lot of your decisions are down to your personal preferences and requirements.

What is Merino wool best for?

When you think of fine and soft garments Merino wool is comparable to cashmere. Some wearers say that it’s even softer. Merino wool base layers are revered for being uniquely gentle against the skin. Each fibre is considerably thinner than a fine human hair, and the natural scales that run up and down all wool fibres are flatter on Merino than on any other kinds of wool. That’s why Merino wool has a smooth, silky feel. Add that attribute to its famous natural softness, and that’s why Merino wool feels great to wear.

The texture, softness and weight of Merino wool mean it’s a great option for socks and gloves, that’ll be silky smooth, lightweight, warm and dexterity and your full range of motion is also retained with fine Merino fibres. 

Merino wool is an especially lightweight wool, and Merino is especially efficient at temperature regulation too. All wool naturally regulates body temperature; Merino wool adds the advantages of  being lightweight and pliable. Due to its tighter crimp from the smaller fibres Merino wool is warmer when it’s cold out and offers greater breathability when you’re warmer.

All these qualities mean that Merino wool is a perfect selection for outdoor wear and especially so when layering. For example, if you’re going on a trekking adventure, Merino wool will keep your body temperature regulated. It’s also extremely comfortable and ensures ease of movement. Merino wool clothing flows with your body’s movement, ensuring a light and comfortable work out or hill climb so that you feel great every step of the way. 

Is Merino wool itchy?

Because of the way the wool scales of Merino wool lay flatter than alternative types of wool, individual Merino fibres also lay flat en masse hence Merino wool is never scratchy or itchy on the skin.

Gloves and socks made with Merino wool are particularly luxurious due to the soft, lightweight and no-itch quality of Merino wool fibres.

How to care for Merino wool

Knowing how to care for your Merino wool clothing ensures that you get the most out of the garments that should serve you well for a good length of time when cared for correctly. Fortunately, one of the main criteria for caring for your Merino wool garments is minimal washing. This is because of the way that mother nature gives wool many advantages.

Merino wool has many natural benefits that make it easy to care for, including: 

• Merino wool is naturally antibacterial

• Merino wool is naturally odour-resistant

• Merino wool wicks sweat away instead of absorbing it

• Residual lanolin remaining after processing means its stain-resistant

After wearing your Merino wool garment, place it somewhere to air out, ideally in a place where the air can circulate. The many attributes of natural wool mean that it with a little care it can remain clean and odour free for several weeks or even months depending on how frequently you wear the item.

Before you wash a Merino wool garment, give it some time to air out. Hang it where air can circulate in and out of it. A wool article can stay clean and odour-free for weeks or months, depending how often you use it.

Consider a good airing before deciding to wash a Merino garment. When it is time to wash Merino wool items, just follow these simple steps.

How to wash Merino wool

If you only learn one thing here, it’s this: do not put Merino wool in a tumble dryer.

Merino wool can be machine washed as long as you have the wool cycle facility on your washing machine. Alternatively Merino wool can be hand washed. Either way make sure that you use cool water and a suitable wool friendly detergent.

Machine wash Merino wool garments: 

1. Add your Merino wool items to the machine with other washable wool items

2. Use a gentle detergent. Your favourite might be suitable, but natural products are always best for wool

3. Select a cool wool setting with a low spin speed and set it to wash. Never wash wool in a hot wash.

4. When you remove it, pat out any residual water and tease into shape and dry flat

Hand wash Merino wool: 

1. Ensure your sink is clean

2. Add adequate luke-warm water

3. Pop your Merino in with the correct dose of suitable detergent

4. Soak for 10 to 20 minutes, gently agitating the water from time to time

5. Very gently squeeze out some of the soapy water, don’t overdo it

6. Drain the sink and rinse the garment at least twice using fresh, warm water

7. Pat dry gently between towels and arrange to dry flat on top of a fresh clean dry towel turning frequently for a couple of days whilst they dry

Whether you wash your Merino wool in the machine or by hand, do not wring out wool clothing. Once you’re ready to dry Merino wool, lay garments out flat on a towel. Flip items over a few times as they dry over a day or two. Never put wool garments in a tumble dryer.

Get even more wash and care instructions for all wool articles on the Icewear website.

Does Merino wool shrink?

Just as Icelandic wool has, Merino wool developed over centuries of Merino sheep responding to their environment. Over generations of the breed, their wool developed the qualities to keep the sheep comfortable in their specific living conditions. 

In the case of Merino wool, its naturally bouncy, for us this means that Merino wool "bounces" lightly back into its original shape after wearing, washing, or packing. This light stretchiness protects Merino wool from shrinking, as well. 

When it’s not properly cared for Merino wool can shrink. Don’t ever attempt to tumble dry Merino wool doing so can quicky shrink it. Washing Merino wool in hot water can result in shrinking as well.

Fortunately, when Merino wool suffers some shrinkage, it can occasionally be stretched and teased back to its original shape. Do this by laying it flat on a towel and stretching it gently after a quick wash by hand.

How to store Merino wool

Given that Merino wool is especially well-suited for outdoor adventures, knowing how to care for Merino wool includes how to store, pack and travel with Merino wool garments. 

The good news is that the structure of the Merino wool fibre ensures Merino garments are naturally wrinkle resistant. Due to the crimp of Merino wool fibre that resembles a tightly coiled spring, Merino garments recoil to their original shape when unpacked.

The same quality of crimp that gives Merino wool that bouncy quality can mean that it might occupy a lot of space in your bag if you allow it to. 

So careful packing using the method of individually rolling each garment and squashing them together makes them take up less room and they’ll bounce back when you unpack them at the other end. Do this by gently slipping your hand around each full roll to remove the Merino garments carefully. Lightly shake out each garment, and they will spring right back to their ready-to-wear shape. 

How to shop Merino wool by weight (and thickness)

Wool fibre thickness is measured in microns. The lower the micron number, the finer and softer the wool. On average human hair is 45 microns thick. Merino wool averages measurements between 17.5 and 24 microns.

Wool can also be measured by its weight and coarseness using grams per metre squared (g/m2). The lower the figure, the lighter the wool. It’s this measurement  that is commonly listed on wool spools and wool patterns and occasionally on garments too, so now you know you can look out for these measurements to establish the weight when buying knitting wool or some clothing items. 

• 150g/m2 – this marks ultra-lightweight Merino wool garments that are perfect for base layers and also great for summer and mild weather.  You could consider this your “everyday wool weight” for a wide variety of uses including indoor use, gentle hiking and touring.

• 180g/m2 – still lightweight but gives excellent breathability while offering a little more protected from the elements. Consider it a Goldilocks standard for weight, warmth and movability when worn for high-intensity activities outdoors like hiking and skiing.

• 200g/m2 – considered by some as the “perfect medium weight” its thin enough for everyday use while also providing optimal body temperature regulation for low-intensity outdoor activities.

• 250g/m2 is a “thermal weight” being excellent for extra low temperatures while still providing the breathability that’s essential for hiking expeditions.

Get shopping for your own Merino wool garments by exploring the range and see how Merino products look now that you know a bit more about Merino wool with the backup of this guide.