How to spin milk

– What? How come? Milk? Real one???

Wrinkling me forehead, disbelief and then intense research. That was my first reaction to the news that you can get and spin milk protein fibre. I got surprised equally much a few minutes later when it turned out the fiber is older than me by a couple of generations and was a way to combat shortages during World War II. But let’s start from the very beginning:

What is a milk fibre?

Chemically it is a mixture of two compounds – casein and acrylic monomer. Where in this in our milk? It’s casein – a group of proteins (lat. “Caseus” – cheese) constituting the majority of proteins present in milk.

A cup of milk maybe?

Since when it is known?

The earliest information about it I found date back to Germany during World War I (Cleopatra’s milk baths do not count in this case 🙂 ). Later patents were assigned sequentially in the 1935 to Italian Lanital (later superseded by Merinova), and in 1937 to the American Aralac. These fibers used to be mixed with rabbit fur in the production of felt hats and with wool, mohair, rayon and cotton in the production of fabrics. Their great time coincided with the time of World War II when economies, busy with war, struggled with a shortage of wool. Very soon after the war ended it turned out however, that no one under normal market conditions remained faithful to ‘dairy’ dresses. At that time, the fiber was lacking strength (held barely 10% of the strength of wool), elasticity and had the unpleasant smell of sour milk when damp.

At this point, no matter how much I would dislike artificial fibers, I cannot deny that these problems were solved by adding them to the casein fibre. What I felt in my fingers during spinning absolutely had nothing to do with the past inconveniences 🙂

My spinning experience

This is how the raw milk fibre looks like. At this point it already looks luxurious, but it shows the real beauty once it is spread lengthwise:

After I’ve spun the first few meters I experienced quite a surprise. I got used to the fact that such silky tops in general are very slippery, while “milk” behaves a bit like candy-floss. The fibers were sort of sticky and I had the feeling I felt something like a slight squeaking of torn cotton when I tried to relax a bandwidth. My guess is that could be the acrylonitrile admixture, which today is present in every modern milk protein fibre. I accept it with pleasure since it is thanks to it I had the pleasure to work with a fibre that did not remind the description of Aralac. The single yarn was extremely strong. I put it somewhere midway between a woolen and ramie yarn and once I triend to break a n-plied yarn I almost hurt my skin.

Another surprise is how much a 1-ply yarn springs back. My original intention was to spin a thin 1-ply yarn, but after first few meters I literally started to worry whether this yarn could be effectively stabilized. Thing worth checking. Thus, I decided to make quite fluffy navajo plied skein.

I spun 50 grams of yarn resulting in having 140 m of navajo plied, 19 wpi yarn in the end, which is quite a nice sock weight. I dipped my skein in water (it absorbs it incredibly fast) and dried it unloaded to prevent elasticity loss.

The fibre is an interesting fusion of old good wool properties with look of modern cellulose fibres like rose, soy or banana. This applies also to dyeing – I made a small try with acid dyes and it went out beautifully. It is even better to dye milk fibre that wool as its surface is scaleless which will prevent it from felting. I was however focused on spinning a truly ‘milky’ yarn so I left my fibre undyed. Finished yarn has gorgeous warm pearl colour and is simply beautiful. Even despite that acrylonitryle. Or rather thanks to it!

How to turn milk into a fibre?

I was wondering whether to write about the production process, or at least – how to write about that without making You bored. Yet since you have reached this point, there is a chance you might be really interested with that: 🙂

The fiber is actually obtained from milk. Extracted casein makes approx. 3% of cow’s milk weight and it makes from 20% to 60% of the composition of final casein – acrylonitrile mixture, thus knowing the latter variable you can easily calculate how many litres of milk was used to produce the blend. Such information, however, I did not found in any place that offers “milk” for sale. Perhaps the increase of its popularity will eventually result in more accurate descriptions. According to my estimates (I assume that casein makes 50% of blend) you need 16.67 grams of milk to produce 1 g of milk fibre.

But returning to the same process: the milk is subjected to skimming and dehydration. Then it is dissolved in alkaline solution, where together with the acrylic monomer (containing at least 50% of acrylonitrile) is subjected to graft polymerization. Combined compounds are then formed into long fibres and cut. Of course, many chemicals are involved in this process, yet the final product turns out to be so safe that it has been certified with Oeko-Tex® Standard 100 (link). It is really good to know this, as this certificate confirms the fibre meets strict guidelines of the European REACH standards and American restrictions as well.

So, in short, that was the milk fibre. Wooly sensations disguised as pearly cellulose – like top. Very interesting fibre!


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  1. Niesamowite! nitka z kazeiny! Można by powiedzieć, że to taki włókienniczy odpowiednik sera 🙂 Będę miała ciekawostkę do opowiadania znajomym krowiarzom. Dzięki 😉 Fajnie, że napisałaś o procesie powstawania, to bardzo ciekawa sprawa.

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