Mercerisation is a process in cotton production. It is a treatment done in one or 2 stages that makes a cotton thread more wonderful, smooth and nicer to work with, which is why I am a fan of mercerised cotton fabrics and threads.
Invented back in the mid 1800s by a guy by the name of John Mercer. At the time, it wasn't so popular a method, but it was improved upon in the late 1800s with the help of industrialisation by another textile manufacturer H. A Lowe.
It is a method where the cotton is placed in a bath of dilute acid and it changes the composition of the fibre making it stronger and giving it a sheen. This makes it easier to dye and print onto, and when woven, a stronger fabric that can be woven finer and at a higher thread count. Mercerised cotton generally won't shrink or the shrinkage rate is far less as as its been pre shrunk under tension during its time in the acid bath.
The second optional stage of mercerisation is running the treated thread through a 'gasser', a gas burner flame, to singe off any little left over threads. This makes your thread super smooth. This second process is not always done, but if a cotton is 'gassed' this is the process it has been run through. 'Pearl' threads are usually gassed which is another reason they are super smooth and have a beautiful sheen.
Mercerisation is usually only done on long staple cotton, which is the more expensive cotton as the threads are long and more easily spun into thread. Types of long staple cotton are Egyptian, Sea Island and Pima. So if a fabric or thread you are working with is made with any of these, it will be a better quality.
The benefits of long staple cotton and mercerisation is you will have a fabric or thread that is easier to work with, stronger, wears and lasts longer, takes dye better so more saturated colours, drapes better, cuts and sews more easily and has less lint and a smoother surface with a nicer sheen. Also, it finger presses a treat and is easier to work with if you are doing small projects or paper piecing.
Mercerisation was the norm in the past for cotton fabrics and threads, but unfortunately its not as common these days, but you can get it and it is worth it. The little bit extra you pay, will come back 10 fold with how lovely it is to work with and how much nicer the finished product will look and it will last longer. A fantastic example of a mercerised cotton fabric is Liberty Tana Lawn, and we all know how lovely that is!
|A box of vintage Mercerised threads|
|Liberty Tana Lawn is a Mercerised cotton fabric|