Wool and hot water- several questions!

Hey all! I’ve been very confused about a few things here and I would appreciate if perhaps you could answer each of these questions. Thank you so much!

1. My whole life I have been told/have read that hot water shrinks clothes. But I have never ever found this to be the case. It is *DRYING* (machine that is) that has always been the shrinking factor. I have washed many clothes in hot water (admittedly mostly cotton) and have found no shrinkage to occur from that. Thoughts?

2. I recently tried lightly cleaning my new (old) WWII tropical worsted wool summer tunic by running hot water (sink) over the stained parts for a few minutes. Immediately I began to wonder if I had just caused some shrinkage. Those parts did dry all wrinkled, but I don’t know if that’s just what wool does or if I’d actually caused shrinkage (?)

3. If hot water does cause wool to shrink, which I’m not sure it does but am curious, is it the sort of thing where something knit will shrink a lot but something made of a woven fabric like this tunic won’t? I just ask because it seems unlikely to me that running hot water over a woven fabric like this would cause it to shrink, especially since it’s held together by stitching with a bunch of other panels, but I have absolutely no clue.

4. If this is in fact an issue, would steaming and steam ironing also pose a risk? And if so, how is wool ever supposed to be smoothed? Only by some industrial process dry cleaners use or ironing with no water?

Thank you!

About point 4 I know I can send my woolen stuff from Rymhart back to them for maintenance and „refreshing“. Something they call a steam bath is involved in that process so steam treatment appears to be possible but no real idea how exactly that might work.

Only available in German but possibly you might push that through a translator.

https://www.rymhart-troyer.de/content/7-refreshing#

I would contact a woolen expert for definitive answers. I'm only guessing.

I suspect a couple things. First, wool has a good amount of oils attached to it, like lanolin and maybe others. Second, wool is a scaly fiber. Under a microscope, you see how it almost looks like it is cracked in rings, almost insect looking (mites). When warm enough water is ran over it, or through it, it removes the oils with it. Then you have these scales that no longer have the lanolin to act like a lubricant to allow it to stretch both over itself and over the scales themselves. As it the wool dries, the fibers do pull inwards, maybe as shrinkage, and get hooked into place. So the weave, and the type of wool, are considerable variables.

A lot of the older garments were stitched with cotton thread, and as we know, cotton does indeed shrink and do odd things when wet and then dries. That's why you get a lot of disfigured wool clothing that was properly washed with cold water. The wool did change, but so did the cotton stitching, but at different levels of shrinkage. Got derailed there a bit. Sorry.

BigBrother said:

Hey all! I’ve been very confused about a few things here and I would appreciate if perhaps you could answer each of these questions. Thank you so much!

1. My whole life I have been told/have read that hot water shrinks clothes. But I have never ever found this to be the case. It is *DRYING* (machine that is) that has always been the shrinking factor. I have washed many clothes in hot water (admittedly mostly cotton) and have found no shrinkage to occur from that. Thoughts?

2. I recently tried lightly cleaning my new (old) WWII tropical worsted wool summer tunic by running hot water (sink) over the stained parts for a few minutes. Immediately I began to wonder if I had just caused some shrinkage. Those parts did dry all wrinkled, but I don’t know if that’s just what wool does or if I’d actually caused shrinkage (?)

3. If hot water does cause wool to shrink, which I’m not sure it does but am curious, is it the sort of thing where something knit will shrink a lot but something made of a woven fabric like this tunic won’t? I just ask because it seems unlikely to me that running hot water over a woven fabric like this would cause it to shrink, especially since it’s held together by stitching with a bunch of other panels, but I have absolutely no clue.

4. If this is in fact an issue, would steaming and steam ironing also pose a risk? And if so, how is wool ever supposed to be smoothed? Only by some industrial process dry cleaners use or ironing with no water?

Thank you!

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My wife is a fabric artist working mostly with wool. She informs me it is not the hot water that shrinks the wool. It is the temperature differential between the hot wash water and a cooler rinse water. I have helped her dye wool with acid dyes and that requires immersion in water just under the boil for an extended period. Once the dye is exhausted the wool is let to sit and return to room temp before the wool can be immersed in tepid water for the rinse process. The wool does not shrink at all during this process.

This is a very interesting thread, giving this a follow.

belfastboy said:

My wife is a fabric artist working mostly with wool. She informs me it is not the hot water that shrinks the wool. It is the temperature differential between the hot wash water and a cooler rinse water. I have helped her dye wool with acid dyes and that requires immersion in water just under the boil for an extended period. Once the dye is exhausted the wool is let to sit and return to room temp before the wool can be immersed in tepid water for the rinse process. The wool does not shrink at all during this process.

Click to expand...

It’s interesting because that’s exactly the experience I ended up having. I spot-wetted/cleaned many parts of the tropical worsted wool tunic I mentioned with hot water (letting it just hang dry after) and then measured parts of it, like the sleeves, and eyeballed others and the shrinkage seems to be zero, which was great. Gradual/natural cooling, if even that was necessary (I’m still not convinced the woven wool would’ve shrunk at all, but who knows ) could’ve been the ticket! Thanks!

BigBrother said:

It’s interesting because that’s exactly the experience I ended up having. I spot-wetted/cleaned many parts of the tropical worsted wool tunic I mentioned with hot water (letting it just hang dry after) and then measured parts of it, like the sleeves, and eyeballed others and the shrinkage seems to be zero, which was great. Gradual/natural cooling, if even that was necessary (I’m still not convinced the woven wool would’ve shrunk at all, but who knows ) could’ve been the ticket! Thanks!

Click to expand...

When washing wool garments I always use tepid water and a natural soap like Dr Bronners. Then rinse it in tepid water as well just to be on the safe side. I dry it flat on a thick towel to absorb the excess water. Hanging can induce misshaping from the wool weight on the hanger.

belfastboy said:

She informs me it is not the hot water that shrinks the wool. It is the temperature differential between the hot wash water and a cooler rinse water.

Click to expand...

I can second that. I have done a lot of wool fabric dying using boiling hot water. While cooling it is important to not move the fabric around. I have done it even with a lot of knit wear like sweaters. It is possible to re-saturate with lanolin after the process to some extent (but I feel warmer in my wool sweaters without a high lanolin content). Woolen baby diapers are treated this way (washing in hot water and adding lanolin after the process).
I have done felting using a tumble drier on a cool setting, after I threw the steaming hot wool fabric into it. This is doing both, fast cooling and moving the fabric. Shrinkage and felting was the wanted result. Slow cooling and no movement has no adverse effect.

When it comes to cotton: cotton only benefits from boiling hot water, ironing the still somewhat moist fabric on a hot setting until totally dry before putting it in the drawer prevents cotton from developing the typical strange smell during longer periods of tight storage. That's another reason why older generations almost ALWAYS ironed cotton in addition to remove creases... Some seam thread materials can shrink, though. Trousers legs can warp, when weft threads are different spun or even just a different batch than the warp threads used in the weave.

This refers only to single material qualities like 100% wool or 100% cotton, blends are a different story.

I posted in various threads now about some wool trousers that just shrunk, but coming back and reading this, I really do wonder if the culprit was the machine vs hand washing. I used delicate cycle and cold water, as I couldn’t do bucket at the time, and I wonder if that caused the shrinkage (1” on inseam and waist).

Not necessarily I'd say. Since some time, wool can be treated by manufacturers to be machine washable. One of the names of this treatment is "superwash". I don't like the idea of treating a fiber which otherwise would be perfectly de-composable and natural like they do with "superwash" wool. But that manufacturers started doing this shows that there are problems with washing wool garments in some washing machines.

Your problem with shrinking of some wool pants is probably an issue worth looking deeper into. Some machines have a "wool setting" or a "hand wash" setting. The idea is basically to reduce movement of the fabric to a minimum, use a lot more water, so the fabric is as much under water as possible. The problem can be the weight of the fabric. When only one half is under water, but the other is above, the weight of the wet fabric from above the water line "sits" on the other half and when moved, the fabric is rubbing against itself much more than if the whole thing is in the water. I don't know, how the delicate setting in your machine uses water and how much and how it moves the fabric around in the drum. You can do an experiment to understand what I mean. If you put a towel in a bath tub full of water and gently move it around while it is entirely submerged but then lift it out of the water. You immediately feel the sudden gain in weight. This effect happens in washing machines quite often, when the water is drained between the rinse cycles. Wool can be "felted" slightly and a weave is tightened, which would explain the loss in length of your pants. So it is mere a mechanical issue than a temperature issue.

That said, "delicates" program does not need to be the right program for wool.

By the way, hand washing can also ruin wool clothing if not done correct. The problem here is also often times too much movement and the lifting of the fabric out of the water to rinse detergents out.

Hope this helps a little.

Cats