r/textiles

I believe it’s primarily to add some value by saying it’s “cotton” or “linen” because these are natural fibers but then diluting it with polyester to try to reduce costs. Is there any material advantage to adding polyester?

Hi everyone ✨

I’m a designer currently based in Brussels, originally from India, and I’ve been working on a very small capsule that brings traditional Indian textiles (like handblock prints, ikat, etc.) into more minimal, everyday silhouettes.

The idea is to make these pieces feel easy to wear in day-to-day life in Europe, not just for special occasions.

I’m in a very early stage right now and would genuinely love some honest opinions from this group:

– Would you see yourself wearing something like this regularly?

– What would make it feel more wearable for you?

No pressure at all, just trying to understand how this resonates with different people before I take it further.

If anyone is open, I’d be happy to share a couple of pieces privately and hear your thoughts :)

If you've owned a polyester workout shirt long enough, you know the trajectory. First few wears, it's fine. A few months in, you start noticing a faint smell even after washing. A year later, the shirt smells the moment it gets slightly damp -- before you've even started sweating. You haven't changed your laundry routine. The shirt has just... absorbed a permanent identity.

That's not your imagination, and it's not a soap problem. It's a biofilm problem.

Bacteria don't just float around loosely on your clothing fibers. Given the right conditions, they attach to the fiber surface, multiply, and build structured communities called biofilms which are thin layers of cells embedded in a self-produced matrix that anchors them to the surface. Biofilms are how bacteria survive hostile environments in nature, and your washing machine qualifies as a hostile environment. The matrix protects the cells inside it from detergent chemistry and mechanical agitation, allowing the colony to survive a wash cycle that would kill the same bacteria floating freely in solution.

What makes textiles particularly susceptible to biofilm formation is the drying cycle between wears. Researchers at Aarhus University tracked what happens to bacteria on cotton and polyester as the fabric transitions from wet to dry after sweating (Møllebjerg et al. 2021).

While the fabric is still wet, most bacteria are loosely associated with the fiber surface. At this stage, a vigorous wash can remove the majority of them and the researchers confirmed this by washing wet textiles and measuring the sharp drop in bacterial counts. However, once the fabric dries, everything changes.

As water evaporates, the thinning film of moisture generates capillary forces -- literal physical pressure created by the surface tension of the shrinking water layer. Those forces press bacteria against the fiber surface. And these forces are surprisingly strong. The researchers calculated that capillary forces during drying can be two orders of magnitude (100×) larger than the energy required for irreversible, permanent adhesion. So, once the fabric is dry, bacteria are essentially cemented to the fiber. They're no longer loosely sitting on the surface; they're mechanically pressed into it.

The practical consequence: washing efficiency drops dramatically once a textile has dried. The researchers quantified this directly : textiles washed while still wet lost most of their bacteria, but textiles washed after drying retained significantly more, regardless of fiber type (Møllebjerg et al. 2021).

And since most people don't wash their gym clothes the moment they take them off, the fabric almost always dries before it hits the machine. Every wear-wash cycle adds another layer of irreversibly adhered bacteria that detergent can't fully remove. Over time, these layers accumulate into persistent biofilms.

A separate study tracked this accumulation through 20 consecutive wear-wash cycles and found that polyester's odor intensity kept climbing over time, while cotton remained relatively stable (McQueen et al. 2014). The permanent funk in your oldest polyester shirt isn't a stain or a residue --> it's a living scaffold that your laundry routine can't dismantle.

This also connects back to what we covered in #3 and #4. The biofilm itself retains sebum and odor compounds from previous wears, creating a pre-loaded nutrient base and odor reservoir for the next round of bacteria. Each cycle feeds the next. The shirt doesn't just fail to get clean; it actively gets better at being smelly.

So, across five posts, we've built a pretty complete picture of why polyester smells worse:
--- it grows the wrong bacteria (#2),
--- feeds them better (#3),
--- doesn't trap their odor output (#4), and
--- accumulates permanent bacterial colonies over time (#5).

In #6, we'll tie it all together with a single unifying concept --> the one physical property that drives nearly every mechanism we've discussed.

from your comments: ENZYMES !
Yes! Leading up to this one, many readers have mentioned using different ways to try to clean all of this - including enzyme-based detergents.
Chemically, it's the right direction. They can help. Protease and lipase enzymes are designed to break down protein and lipid structures, which includes both the biofilm matrix and the sebum residues that feed bacteria between wears. If you're washing synthetic sportswear, enzyme detergents are a better tool than conventional surfactant-only formulations. But it's worth understanding what they're up against. The primary adhesion mechanism after drying isn't chemical, it's physical.
Capillary forces mechanically press bacteria into the fiber surface with an energy that dwarfs what chemical bonds contribute. Enzymes can degrade the biological material, but they can't reverse the physics of how it got cemented there. They improve the situation meaningfully without solving it completely, which is why even well-laundered polyester sportswear tends to accumulate odor over time.

References: Møllebjerg, A. et al. (2021). The Bacterial Life Cycle in Textiles is Governed by Fiber Hydrophobicity. Microbiology Spectrum, 9(2), e01185-21.

McQueen, R.H. et al. (2014). Axillary Odour Build-up in Knit Fabrics Following Multiple Use Cycles. International Journal of Clothing Science and Technology, 26(4), 274–290.

So far in this series we've focused on bacteria in terms of which species grow, what they eat, and why polyester feeds them better. However, there is a second half to the odor equation that has nothing to do with bacterial growth. It's about what happens to the smelly molecules after bacteria produce them.

This matters because two fabrics can generate similar amounts of odor compounds and still smell completely different to your nose. What matters is whether those compounds stay locked inside the fiber or escape into the air.

This comes down to a property called moisture regain which can be described as how much water a fiber holds onto after it feels dry to the touch.

When researchers at Aarhus University measured the residual water content in cotton and polyester after both fabrics had fully dried under identical conditions, cotton retained about 2.2% of its weight in water. Polyester retained ten times less than that at only 0.23% (Møllebjerg et al. 2021).

That thin film of residual moisture in cotton isn't just sitting there. It's doing something useful: dissolving and trapping volatile fatty acids (the odor molecules that bacteria produce). Those compounds are water-soluble, and as long as they're dissolved in the fiber's retained moisture, they aren't evaporating into the air and reaching your nose. The fiber is effectively sequestering or holding in the stink till you can wash it out in the laundry.

Polyester holds almost no residual moisture. So, as soon as bacteria produce odor compounds, those molecules have nowhere to hide. They sit on a dry, non-absorbent surface and volatilize freely into the air. The result is faster, more intense odor release, even if the total amount of odor compounds produced is similar.

This mechanism also explains one of the more counterintuitive findings in the textile odor literature. Wool is a hydrophobic fiber, its surface actually repels water, similar to polyester. You'd expect it to have a similar odor problem. But wool consistently scores among the lowest fabrics for perceived odor intensity after wear, despite supporting high bacterial counts (McQueen et al. 2007).

The explanation lies in wool's unusual structure. While the fiber surface is hydrophobic, the fiber interior is highly hygroscopic, meaning it absorbs and retains moisture within its core. This gives wool a high moisture regain despite its waxy outer layer. That internal moisture reservoir traps odor compounds the same way cotton, bamboo, and hemp do, preventing them from becoming airborne. Wool is essentially a stealth moisture trap with water-repellent on the outside, odor-absorbing on the inside (Møllebjerg et al. 2021).

So, what does this mean for the overall odor picture?

Polyester gets hit from both sides. It selectively grows the smelliest bacteria (#2), feeds them more efficiently through better sebum access (#3), and does nothing to trap the odor molecules those bacteria produce (#4). It's a three-stage amplifier: more of the wrong bugs, better-fed bugs, and no odor containment.

Cellulosic fibers like cotton, hemp, bamboo, lyocell, and other plant-based or regenerated-cellulose materials have the opposite profile at each stage. They don't preferentially grow odor-causing species, they don't coat themselves in bacterial food, and they retain enough moisture to sequester volatile odor compounds before they reach the air.

But we're not done yet. There's one more mechanism that makes polyester's odor problem compound over time and it explains why your oldest gym shirt is always your smelliest, no matter how many times you wash it.

That's coming in #5. Till then, let me know if you have any comments or questions about what we've covered so far. I think the wool paradox is pretty interesting - anyone else?

References: Møllebjerg, A. et al. (2021). The Bacterial Life Cycle in Textiles is Governed by Fiber Hydrophobicity. Microbiology Spectrum, 9(2), e01185-21.

McQueen, R.H. et al. (2007). Odor Intensity in Apparel Fabrics and the Link with Bacterial Populations. Textile Research Journal, 77(7), 449–456.

I need help finding 100% mulberry silk satin fabric 19 momme but it's so confusing can I get some help kind strangers

Hello ,

Im currently looking for high end fabric factories in mumbai ( just the raw material )

Does anyone know names ?

I've recently joined my family business, we are a 52year old export house based out of Bombay, INDIA. We primarily make clothes for international retail brands. Our production capacity is currently working at 80%, looking to optimise that by taking on new clients. Minimum MOQ is 100 pieces. WE DEAL IN ALL KINDS OF KNITS, DENIMS, Fabrics you name it, we got it. If anyones looking for manufacturers HMU

People get fooled all the time by reproductions. A few things that actually help:

Smell it. Old natural fiber textiles have a distinct musty, slightly sweet smell from decades of oxidation. It's hard to fake and hard to wash out completely. Reproductions smell like sizing, chemicals, or nothing at all.

Look at the selvage. Pre-1960s woven fabrics typically have a narrower selvage width, usually under 60 inches. Modern looms run wider. If someone is claiming something is 1940s but the fabric width is 66 inches, something is off.

Check the dye behavior under UV light. Synthetic dyes from the 1950s onward fluoresce differently than natural dyes. A blacklight is one of the cheapest and most reliable tools for roughly dating a textile. Natural indigo, madder, and weld dyes absorb UV rather than fluoresce. Most modern synthetic dyes glow.

Feel the hand of the fabric. Natural aging changes the cellulose structure of cotton and linen in a way that's genuinely difficult to replicate. Old cotton has a softness that's different from washed modern cotton — less uniform, slightly uneven in texture.

Thread count is not a quality indicator for vintage. Modern fabrics regularly hit 400+ thread count. Pre-industrial textiles were often 80-120 thread count but far more durable because the individual threads were longer staple and more tightly spun.

The reproduction market has gotten very good. But the physical and chemical properties of genuinely aged textiles are harder to fake than people think.

How to change the color of my Puma hoodie from light blue to black?

Like, what equipment should I use?

Let's start with the thing most people don't know: sweat doesn't smell. Fresh sweat is about 99% water, with some salts, amino acids, and a small amount of lactate and urea. If you collected it in a vial, you'd barely notice anything. The odor you associate with a hard workout isn't coming from what your body secretes. It's coming from what bacteria do with it.

Skin bacteria metabolize the organic compounds in sweat and sebum (the oily secretion from your skin's sebaceous glands) and they produce volatile fatty acids as metabolic byproducts. Those short-chain fatty acids range from acetic acid (vinegar) to isovaleric acid and those are what you're actually smelling. The musty, sour, sweaty notes that hit you when you open your gym bag? That's bacterial metabolism, not human perspiration.

So far, straightforward. Here's where it gets interesting.

You'd expect the bacteria on your shirt to be the same as the bacteria on your skin, after all, they transferred from one to the other during your workout, right? But when researchers at Ghent University collected T-shirts from 26 people after an hour-long spinning session and profiled the microbial communities using DNA fingerprinting (DGGE), they found something surprising: the textile microbiome was fundamentally different from the skin microbiome (Callewaert et al. 2014, Applied and Environmental Microbiology).

On your axillary skin (under arms), the dominant odor-producing bacterial family is Corynebacterium. These are the bacteria most responsible for the characteristic sharp, pungent body odor that develops in your armpits. They're well-adapted to the lipid-rich, low oxygen environment of the skin surface, and they're efficient at converting sweat precursors into the three main classes of bad-smelling underarm compounds: short branched-chain fatty acids, steroid derivatives, and sulfanylalkanols.

But Corynebacterium can't really thrive on fabric. In the Ghent study, corynebacteria couldn't be detected on any of the 26 T-shirts by DNA fingerprinting, couldn't be isolated by culture in petri dishes, and showed declining populations on every fabric type tested in controlled lab experiments — polyester, cotton, nylon, wool, viscose, acrylic, and fleece. Every single one. The species that dominates your armpit odor simply doesn't survive the transition to fabrics.

So, if it’s not corynebacteria smelling on your clothes, what's actually growing on your shirt?

The textile microbiome turned out to be dominated by Staphylococcus and Micrococcus species. Staphylococci were found on practically every shirt regardless of fabric type — they're generalists. However, Micrococcus showed a striking pattern: it appeared on nearly every synthetic shirt and was almost completely absent from 100% cotton shirts. This wasn't a subtle statistical trend. The DGGE banding patterns showed clear, visible preferential enrichment of micrococci on polyester and other synthetic fibers.

Why does this matter for odor? Because Micrococcus species are known to be potent odor generators. They can fully catabolize several kinds of fatty acids into volatile malodor compounds. They're related to corynebacteria and share some of the same metabolic toolkit for producing stink, but unlike corynebacteria, they thrive in the oxygen-rich, fiber-surface environment of clothing rather than the oily, oxygen-poor environment of underarm skin.

So, the picture that emerges is this: your shirt doesn't smell like your armpit, and it's not supposed to. The odor on your shirt is produced by a different microbial community that assembles itself based on the conditions the fabric provides. Your skin seeds the initial population during sweating, but the fabric environment selects which species flourish and which die off. That selection, which turns out to be heavily dependent on what your shirt is made of, is what determines whether your post-workout laundry smells merely lived-in or genuinely offensive.

That raises the obvious next question: if polyester and natural fibers can host similar total numbers of bacteria, why does polyester consistently smell so much worse?

That's coming in #2.
Before I finalize that, let me know what you think about this first piece in terms of length and depth of language so I can adjust - and of course, if you have any questions, let me know in the comments.

References: Callewaert, C. et al. (2014). Microbial Odor Profile of Polyester and Cotton Clothes after a Fitness Session. Applied and Environmental Microbiology, 80(21), 6611–6619.

 

Making a project and I can’t seam to find any good shop in MUMBAI with the crazy good looking jersey/ spandex with cool prints.

I’ve noticed this repeatedly. A fabric looks great in photos, but feels different in real use. Lighting and presentation play a big role, but the actual performance only shows up once you touch it.

I’m sharing this short breakdown because it hits on a key variable: GSM. As the video explains, a shirt can look exactly the same on your monitor, but the difference between 160 and 260 GSM is the difference between something that feels "airy" and something that feels "dense" and structured. You can't photograph weight. It’s a good reminder that if you aren't looking at the technical specs and getting physical swatches, you’re just guessing.

Most people assume post-workout odor is just "sweat smell" --- "it's inevitable, the same on every fabric, and the only variable is how much you sweat."

It turns out, almost none of that is true. The bacteria on your gym shirt are entirely different species from the bacteria on your skin, and which ones thrive depends on molecular-level properties of the fiber they're living on.
So, why does a polyester shirt smell worse than a cotton one after the same workout, even when both carry similar amounts of bacteria? I'm a polymer scientist with a background in fiber chemistry and textile R&D, and that question is where this series starts.

There's a surprising amount of peer-reviewed research on this topic, and the real answers are more interesting than most of what circulates online. The science involves microbial ecology, surface chemistry, and some counterintuitive findings that are worth understanding-- especially if you're someone who cares about what you're putting against your skin every day.

Each post in this series covers one piece of the puzzle, explained in plain language with the studies cited so you can dig deeper if you want - or post a question and I'll respond. Here's what we'll work through:

#1 Are the bacteria on your shirt even the same ones on your skin?

#2 If two fabrics carry similar amounts of bacteria, why does one smell dramatically worse?

#3 What are textile bacteria actually eating, and why does one fiber type serve it up better?

#4 How do some fibers trap odor molecules while others let them fly?

#5 Why does your old gym shirt smell worse than your new one — even right out of the wash?

#6 Is there one physical property that ties all of this together?

#7 And what does all of this actually mean for choosing fabrics that work?

Each of these will be a short easy read (~3 minutes?) but super informative…and sometimes surprising. The first one is coming soon.

Spoiler for #1: the bacteria making your clothes smell aren't even the same species as the ones in your armpits!

We've been making men's bottomwear fabric — for chinos, cargos, trousers, etc — for years. Good quality, solid relationships, great scale. All local.

Now I want to build an export division. I have the manufacturing backbone. What I don't have is the roadmap.

If you export textiles from India, or you've helped someone do it — I genuinely want to learn from you. Not looking for a pitch. Just real conversations with people who've been there, done that.

Everyone in your comments is someone you know. Your first 50 sales were people who felt obligated. You've been optimizing the wrong thing.

Getting a friend to buy is easy. Getting someone who has never heard of you, owes you nothing, and has 10 other options to pull out their card — that's the actual game. And most small brands never figure out how to do it.

The weird thing is the product is usually fine. I've seen genuinely bad products sell well and beautiful products sit. The difference is almost never quality. It's whether a stranger feels like this brand is for them before they even look at the price.

That feeling comes from content, not ads. Ads show a stranger your product once. Content makes a stranger feel like they've been watching your brand for months before they ever visit your page. By the time they land on your site they're already halfway sold.

The brands that crack this aren't posting better product photos. They're posting content that makes a specific type of person think "this brand gets me." Niche is not a weakness at this stage. It's the only way a stranger decides you're worth paying attention to.

Stop trying to appeal to everyone. The wider you cast it the more invisible you become.