Two kinky curly wefts can look identical in the bag. Wash them ten times and they part ways. The difference is not care or luck. It is what was done to the strand to give it that coil in the first place, and almost nobody selling hair will tell you which method they used.
The two ways to put a coil in straight hair
Most human hair arrives from the donor straighter or wavier than the textures our customers wear. To make it kinky or coily, the industry does one of two things.
The first is chemical texturizing: a perm solution breaks the load-bearing bonds inside the strand and re-forms them around rods. It is fast and cheap, and it permanently weakens the hair, the same way a relaxer or perm stresses your own.1 The pattern sits shallow. Washing loosens it a little each time, heat loosens it faster, and the strand grows brittle at the pace of the processing it carries.
The second is steam. The hair is set around forms and shaped with pressurized steam, no chemistry, its permanent bonds intact. It takes longer and costs more, which is why it is rarer. The pattern is set into the strand through the bonds that answer to water and heat, so water does not erase it; water restores it. A steam-set coil that looks tired springs back after a wash. That reversion is the signature of the method.
What steam actually does to the strand
Hair holds its shape through two kinds of bonds inside the cortex, the core of the strand. Disulphide bonds, formed between the sulphur atoms of cysteine, are the strong permanent cross-links that make hair what it is. Alongside them sit far weaker hydrogen bonds, and those are the ones that break and re-form with water and heat, which is why a wet set or a blowout lasts until the next wash and then falls out.1 Steam-setting works with the strand instead of against it. The hair is wound onto forms in the coil pattern it will keep, then held there while pressurized steam heats it evenly all the way through. As it cools in place, the hydrogen bonds re-settle around the new shape while the disulphide cross-links, the permanent structure, are never broken. The coil becomes the strand's resting position.
That is why water is not the enemy of a steam-set weft. Wetting the hair relaxes those same hydrogen bonds, and as it dries it returns toward the shape it was set in. The pattern lives in the strand's core, not on the surface, and no permanent bond has been dissolved or rebuilt to fail later. It is the same principle as a roller set, done to raw strands that were never chemically altered, which is what keeps the fibre sound.
Why chemically texturized hair degrades
Chemical texturizing takes the opposite route. A reducing agent, usually a thiol such as ammonium thioglycolate, ruptures the disulphide cross-links that hold the strand together, the hair is forced around rods into a coil, and an oxidizing neutralizer such as hydrogen peroxide locks the shape by reforming those bonds in new positions.2 The rebuild is never complete or even. Some cross-links re-form, some do not, and the strand ends up measurably less rigid and less resistant than it began.1 You are left with a coil that exists because the strand was partly taken apart.
From there it only goes one direction. Every wash swells an already compromised strand and a little of the pattern drifts loose. Every pass of heat accelerates it. The cuticle, the protective outer layer, gets swollen and lifted by the same chemistry so the straightener can reach the cortex, which leaves the hair snagging on itself, tangling, and frizzing.1 This is not a care failure. It is the method degrading on schedule, the way a relaxer grows out whether you baby it or not.
Steam-set vs chemically texturized, side by side
| Steam-set from raw hair | Chemically texturized | |
|---|---|---|
| How the coil is made | Shaped with pressurized steam, the strand's permanent bonds left intact | A reducing agent breaks the disulphide bonds, then an oxidizer reforms them in a new shape |
| Strand strength | Unchanged, the hair stays as it grew | Measurably weaker and more fragile |
| How deep the pattern sits | Set deep, so water restores it | Sits shallow, so each wash loosens it |
| Over time | The coil springs back after a wash | The coil drifts looser and frizzier |
| Response to heat | Holds unless repeatedly flat-ironed on high | Loosens faster |
| How to spot it | No perm smell, the pattern returns when wet | A perm-solution sharpness, the pattern fades |
How to tell what you bought
- Smell the weft when it is wet. A lingering perm-solution sharpness points to chemical processing.
- Watch the pattern across washes. Chemically set coils drift looser and frizzier. Steam-set coils return.
- Ask the seller directly how the pattern was set, and notice whether the answer is specific or a shrug.
How to test hair you already own
If a weft is already in your closet, you do not have to guess. Wet a small section fully with plain water and let it air-dry without stretching or product. Steam-set hair draws its coil back up and settles close to the pattern you first saw. Chemically set hair tends to dry looser and frizzier than it went in, because the water loosened bonds that were already fragile. For a second read, stretch one shed strand slowly between two fingers: sound hair gives a little and springs back, while over-processed hair stretches too easily, feels gummy when wet, or snaps.
Why this changes how the hair blends and holds moisture
The method you cannot see is the one you feel every day you wear the hair. Blending depends on both textures answering to water the same way. Your own 4C or kinky hair coils tighter in humidity and relaxes when wet, and a steam-set weft does the same, because its pattern responds to moisture instead of resisting it. The seam at your leave-out stays quiet through rain, sweat, and a spray bottle. A chemically set weft answers to humidity unevenly, since its cuticle and bonds were disrupted in patches, so one section swells while another sits flat and a blend that looked clean on install day starts to separate.
Moisture follows the same logic. Intact hair takes in water and leave-in evenly and releases it slowly. A processed strand with a lifted cuticle drinks in one spot and repels in another, which is why chemically texturized wefts can feel dry no matter how much product you pile on. Matched chemistry is what lets one moisture routine serve your hair and your extensions at once.
How long the pattern lasts
Longevity is really a question of which method you bought. A steam-set weft, cared for reasonably, holds its coil for the working life of the hair, because washing renews the pattern rather than wearing it down. A chemically set weft is on a clock from the first wash, loosening until it no longer reads as the texture you paid for. Same length, very different runway. Shop the hair against how long the coil will actually survive, not how it looks in the listing photo.
Where we stand
Every Adéorí pattern is set with steam from raw hair sourced in Southeast Asia, cut and bundled in one direction so the cuticle stays as it grew, then machine-sewn into reinforced wefts of roughly 100g. Our founder walks the factories herself and watches the hair arrive in its natural state. The longer version of that story is in Our Story, and the question of where hair actually comes from gets a straight answer in our FAQ.
One warning, since honesty cuts both ways: repeated high-heat flat-ironing will loosen any steam-set coil permanently. Above roughly 150°C the keratin itself begins to denature, and sustained heat disrupts even the disulphide cross-links, a change the strand does not recover from.3 The method protects the strand; it does not make it immortal. Treat heat as an occasional tool and the pattern holds for the life of the hair.
1 Barreto, T. et al. (2021). Straight to the Point: What Do We Know So Far on Hair Straightening? Skin Appendage Disorders (Karger), via PubMed Central. pmc.ncbi.nlm.nih.gov/articles/PMC8280444.
2 Ophardt, C. (Elmhurst College). Permanent Hair Wave. Chemistry LibreTexts. chem.libretexts.org.
3 Lima, C. R. R. C. et al. (2026). Thermal Induced Changes in Cuticle and Cortex to Chemically Treated Hair. Biopolymers (Wiley), 117(1):e70071. ncbi.nlm.nih.gov.