Yet he was so beautiful.
You still remember those magical moments you spent with him. You felt so good when you wore it, it knew how to make you look good.
He who was your size.
©
You were so happy next to him.
But that's it, it's a thing of the past, because here you are in front of a pile of disintegrated wool in size 12 years, ready to be passed on to your little nephew.
After explaining to you why your jeans tore and how your sweater pilled, I'm going to tell you what happened behind the scenes of this shrinkage.
©
We're going to see together what happened in there.
And as usual, we will take a quick look at the precautions and solutions that you have on hand, just to avoid a collection of boiled stitches for elves.
Well, unless it's your passion. No judgment.
BUT WHAT HAPPENED IN THIS WOOL SWEATER?
There are three main factors that play into the shrinkage of a knitted sweater:
- The heat
- Friction
- humidity
Now, surprise: these three elements are found in your washing machine.
Here's a rare photo of three serial sweater killers together in the same room. (Photo credit: Tina Bosse - Unsplash.com)
But before discovering how they can halve the dimensions of your knitted companion, let's take a look at its constitution.
Before arriving on your shoulders, a wool sweater is knitted from yarns, which are themselves made up of fibers from animal fur.
These fibers are therefore natural. They live and have a whole set of small scales on the surface, giving the wool its divine insulating properties.
A very telling microscope view: on the left, we can distinguish the different scales that each wool fiber can have.
But these scales are a little finicky.
In fact, they tend to want to serve as a “bridge” from one fiber to the other, linking the latter together. We are talking about hydrogen bonds.
LA MINUTE SCIENCE: A HYDRO-WHAT LINK?
You have probably already attended a chemistry course on molecules, sprinkled with a few equations on the bonds they can have between them. All accompanied by a few headaches no doubt.
A hydrogen bond is simply a molecular bond involving an atom... of hydrogen. In this particular case of bond, it is the latter which will make the bridge between the two other atoms. The most telling example being water.
In our sweaters, the hydrogen atoms will be there to bridge the gap between the proteins in the wool fibers (from animal hair) or the cellulose in the cotton fibers (which is plant-based) .
When the mesh is knitted, hydrogen bonds are created and hold the fibers together. Air is also trapped between these fibers, marking the distances between them.
To summarize, your wool knit sweater therefore has:
- Of wool fibers having scales along their entire length,
- Which are mostly separated from each other by the air between the wires,
- But part of which is entangled by a hydrogen bond.
Here, it is cotton but we can clearly understand how the fibers are distributed: with the air between them and the hydrogen bonds which are created between those which are in contact. (Photo credit: University of Plymouth - phys.org).
Now let's put all of this in a washing machine, for a “mass sweater destruction” program at 40 degrees.
The first thing that will happen to your mesh is a good bath of hot water. We therefore already find here two of our three factors mentioned above: humidity.
While this will cause the fibers to swell while detaching them from each other, the heat will happily disorganize their scales: they will rise up to emerge and mix in all directions to compress lengthwise. fibers.
On contact with water and heat, these small scales straighten up and become completely anarchic (Photo credit: Darbymade.com).
The scales will then only need one thing: to find those of their neighbors to bond with them through entanglement. And that's good (or bad, for us), since in this laundry bath, there is no longer any air to separate the threads.
This is where the fibers tighten together, allowing our third factor to intervene: the friction caused by the drum movements. This friction will allow the scales to quietly connect one fiber to another.
But it is at the drying stage that the final blow comes: the water evaporates, and new, much more numerous hydrogen bonds are created to form a denser and more compact network.
And when a spin at 2600 revolutions per minute is involved, I let you imagine to what extent the compression by centrifugal force that it involves will help the fibers to join together forever.
Here's a large-scale look at what your sweater is experiencing at this moment.
To give it the final blow, a quick spin in the dryer would only aggravate the “heat effect” on the fiber, while damaging it in the process.
Once dry, your mesh is completely tightened, compact and full of hydrogen bonds which have made it lose two sizes.
They say here that she felted.
A felting which will not go much further in the next washes, since there will not be a lot of additional connections to generate.
WHAT IF I TAKE ANOTHER MATERIAL?
As you may have read above, cotton sweaters are also subject to hydrogen bonds via the cellulose atoms contained in their fibers.
So you would think the same thing would happen if you chose this composition.
And it's true: a cotton knit will also be subject to shrinkage during its first wash. But this shrinkage will be much less marked.
To give you an order of magnitude, washing at 40 degrees can cause a wool sweater to lose around twenty centimeters, compared to one to five centimeters for its cotton counterpart (linen could move slightly more, but we will stay on the order of one or two centimeters difference compared to cotton). In subsequent washes, the cotton will hardly move.
If we can see this difference in shrinkage between two sweaters, it is quite simply because the same thing does not happen in their insides.
The very constitution of the fibers and their scales being different, the wool shrinkage process that I described to you above has a much less impact on cotton.
However, cotton fibers, before landing in a sweater, are stretched to make a thread. These threads are then knitted to obtain the weave of your piece. During the first hot water bath, the fibers will seek to return to their initial shape, tightening the fabric on itself.
It is from these small white flowers that we stretch the fibers to make threads (Photo credit: Trisha Downing - Unsplash.com).
This phenomenon is as present for knitted cotton pieces as for denim and other fabrics, such as jersey or poplin. It can go up to a loss of 30%.
And it is to anticipate this effect that certain manufacturers of cotton pieces carry out pre-washes to restore the final shape of the fabric before sale. This explains why the majority of cotton clothes move very little when washed at home.
Other brands go so far as to add one or two centimeters, to the sleeves of a shirt for example, to anticipate this possible shrinkage.
Although a cotton sweater will be significantly less thermoregulatory in harsh climates, it will nevertheless be less likely to move during its rotations in the machine drum.
THE QUESTION OF SYNTHETIC FIBERS
This is even more the case for a synthetic fiber sweater: of plastic origin, its fibers have no scales.
© On these acrylic fibers, you can see the absence of scales on the surface. (Photo credit: University of Plymouth - phys.org).
In addition, the thermal stabilization treatments they have undergone will make them less sensitive to the heat of the water.
No scales, no tangling from one fiber to another.
No reaction to hot water, no transformation of fibers.
No living fiber, no significant shrinkage.
An oil knit will therefore be the least likely to lose a size when washing. But if you choose the plastic side of force, you will be able to forget all the advantages of a natural material: your sweater will keep you less warm, it will be less breathable and will age significantly less well than its wool counterpart.
For both cotton and wool, the knitting method can also influence, to a lesser extent (the nature of the fiber will remain the primary factor), the “shrinkage margin” of a sweater.
For example, a more open or “loose” wool knit will have more air between its fibers, the compression margin will therefore be greater when the new hydrogen bonds are created. But these meshes are also often the heaviest: once extended, they will more easily tend to stretch again under their own weight.
TO PREVENT SHRINKAGE, WHAT DO I DO?
There, I can only refer you to our clothing care tips, which will avoid both disasters for your sweaters and minor incidents for your other cotton pieces.
You'd really have to be heartless to cruelly throw this sweet treat in the dryer, right? (Photo credit: Victoria Bilsborough – Unsplash.com).
Our trip to the land of fibers can help you understand the benefit of a machine wool program, simply aimed at reducing the impact of two out of three shrinkage factors:
- Heat, by simply reducing the water temperature
- Friction, by limiting the number of revolutions per minute while adapting their speed to coax your mesh. This limits the opportunities for friction of the fibers and therefore the formation of hydrogen bonds between them.
©
Also think about this little bonus: a laundry bag to limit friction.
These advantages are found even more when washing by hand, where friction will be the least present (note that your sweater will shrink by at least 1 centimeter the first wash, whatever happens.).
In the latter case, I can share with you a lesson learned from personal experience (if anyone is looking for a De Fursac sweater for their 8 year old child, they can contact me in the comments): wash really cold, and do not wash not your sweater in the spin cycle. Lay it directly flat (because if you hang it, it will deform under its own weight).
Indeed, if you wash your sweater in slightly hot water, and then follow it up with a ride at 400 revolutions per minute, the little heat, humidity and compression by centrifugal force will be enough to lose a few centimeters meaningful to your precious companion.
AND TO CURE IT?
On the vast lands of the web, you will find several recurring methods to reduce the damage to a shrunken wool sweater. They suggest, at best, the use of shampoo or fabric softener.
Nicolò suggests using a shampoo with lanolin, a natural oil present in sheep's wool.
Some conditioners contain it, but you can also add a few pure drops of lanolin to your bath water.
But I'm sorry to tell you: unless you can untangle the tangled scales from the fibers under a microscope, you won't be able to restore it to its original size.
These methods can always save a few centimeters, if the losses are not too great:
- Soak your mesh in a basin or bathtub of lukewarm water with a dose of conditioner or fabric softener.
- Leave for several hours, until the fibers swell again and the softener allows part of the scales to let go, detaching certain hydrogen bonds.
- Take out the sweater and gradually begin to pull on the sleeves and body, focusing on the most compact areas. Pulling on it while it is still wet will separate some of the fibers and prevent them from bonding together again.
The operation can be repeated, but your sweater will inevitably be deformed.
BUT SO, WHEN IT RAINS IN SUMMER, DO THE SHEEP SHRINK TOO?
I think not, because it is fiber blocks and not a weave. But you surely have your theory to share with us in comments.
