If you’ve ever ordered a product in a flat pouch, picked up a sample at a trade show, or wondered why some pouches feel “off” when you unbox them, you’re not alone. As a flat pouch supplier who’s worked with food manufacturers, skincare brands, and pet product companies for over eight years, I get at least a dozen questions a month that boil down to one: Do flat pouches have a smell? Flat Pouch
It’s a loaded question, honestly—because the answer isn’t just “yes” or “no.” It’s tied to materials, manufacturing processes, how the pouch is stored, and even the products going inside it. I’ve spent countless late nights in our factory’s quality lab testing samples, walking through production lines with our material engineers, and troubleshooting complaints from clients who’ve thought their entire batch of goods was ruined because of a weird plastic odor on their new flat pouches. Let’s break this down the way I break it down for our clients, without the confusing industry jargon.
First, let’s start with the basics: what are flat pouches made of? Most of the flat pouches we supply aren’t made of a single plastic. If you’ve ever peeled open a used flat pouch, you’ve probably noticed it has layers—think of it like a sandwich, but for packaging. The most common layers are: a food-safe or product-safe inner layer (usually polyethylene, or PE, if it’s for food), a middle layer for strength or barrier properties (like nylon, to stop grease or oxygen), and an outer layer for printing and UV resistance (often polyester). Sometimes we add an extra layer of aluminum if a client needs extra protection from light or moisture, like for specialty coffee or prescription supplements.
Each of these layers is made with resins, additives, and adhesives—and that’s where smells can come from. The key here is that not all materials are equal. Back when I first started in this industry, a lot of pouches were made with cheaper resins that had residual “plastic” odors, leftover from the chemical reactions that turn crude oil into plastic pellets. Those pellets can have a faint, chemical smell if they’re not processed correctly, especially if they sit in a warehouse for months before being turned into film for pouches. Adhesives used to bond the layers together can also contribute odors if they’re not fully cured (dried) during manufacturing. We used to get a lot of calls about pouches that smelled like “glue” back in 2016, before we switched to solvent-free adhesives for 90% of our production lines. Solvent-based adhesives were cheaper, but they left behind tiny amounts of volatile organic compounds (VOCs) that give off that sharp, chemical smell if not fully cured.
But here’s the thing: most of the time, that “pouch smell” isn’t a defect in the material—it’s a temporary byproduct of manufacturing. When our flat pouches come off the production line, they’re rolled up tight and packed into boxes immediately. That traps any leftover odors from resins or adhesives inside the pouch, and over time, the smell gets concentrated. We’ve run tests where we take a fresh pouch, seal it right after manufacturing, and have a panel of our staff rate the smell—most say it’s a faint, mild plastic scent, not offensive. But leave that sealed pouch in a box for two weeks, open it, and that same faint scent feels stronger. It’s just like leaving a new t-shirt in a plastic bag for a week; when you pull it out, it has that “new” smell that goes away after one wash. Same concept with flat pouches.
Now, when do flat pouches have a smell that’s a real problem? It’s usually one of three scenarios. The first is cross-contamination during manufacturing. We have strict protocols for cleaning our lines between producing pouches for food and non-food products, but I’ll be honest—on busier days, if a line wasn’t fully purged of residual material from a previous run, you might get a pouch that has a faint smell of whatever was made before. For example, a pouch that previously held citrus-flavored powder might leave a tiny scent on the film, or a pouch made with a different type of resin. We caught this issue two years ago when a small coffee roaster complained their new flat pouches smelled like mint—turns out we’d run a batch of mint tea pouches the day before, and the line wasn’t fully cleaned. We fixed that by adding a mandatory line purge step every time we switch materials or products, so that’s a mistake we haven’t made since.
The second scenario is pouches stored in poor conditions. I’ve seen clients receive our flat pouches and store them in a hot, damp warehouse for months, and then complain about a strong, mildew-like smell. Humidity and heat break down the plastic layers over time, causing the additives in the resin to leach out, which creates off odors. Or if pouches are stored near chemicals, cleaning supplies, or even strong-smelling products like paint or wood, the plastic can absorb those odors like a sponge. Plastic is porous enough that it can pick up smells from the surrounding air, especially if it’s left sealed for a long time. I once had a skincare client who thought their flat pouches were defective because they smelled like cigarette smoke—turns out their warehouse manager was storing the pouches in a back room where employees smoked, and the plastic had absorbed the smell before they even opened the boxes. That’s not a pouch defect; that’s storage error.
The third, and most common, scenario is when the pouch’s smell is reacting with the product inside it. This is a big one for our clients, because it’s not about the pouch itself—it’s about how the two interact. For example, some products that are high in oil, like nut butters or essential oils, can react with the inner layer of the pouch, causing the material to break down and release a scent that mixes with the product. Or some acidic products, like citrus juices, can also break down the resin over time, leading to off smells. We run compatibility tests with every new product client brings us, and we recommend specific inner layers to prevent this. For example, if a client is packaging highly acidic tomato sauce, we use a cross-linked PE inner layer that’s more resistant to chemical reactions, so it won’t leach or absorb the sauce’s scent. If we skip that step, the pouch might start to smell sour after a few weeks, which will ruin the product inside.
Now, let’s talk about the good news: modern flat pouch manufacturing has come a long way. When I started, we used to send every batch of pouches to a third-party lab for odor testing, and we rejected about 8% of batches due to smell issues. Now, with our updated processes—solvent-free adhesives, high-purity resins, strict line cleaning protocols, and post-production air-flushing of pouches to remove any trapped fumes—our batch rejection rate for odor-related issues is less than 1%. We even have a “low-odor” option for clients packaging sensitive products, like infant formula or fine fragrances, where we bake the pouches at low temperature after production to remove any remaining residual odors. We test these low-odor pouches with our own sensory panel, and we also send samples to independent labs to measure VOC levels—we make sure they’re way below the limits set by FDA for food contact materials and EU regulations for consumer products.
I also want to address a misconception that a lot of new suppliers push: that “all natural” or “uncoated” flat pouches have no smell. That’s not true. Natural materials like paper or plant-based plastics often have their own natural odors, and plant-based plastics can actually have stronger temporary odors from the bio-resins used to make them. We worked with a client last year who wanted 100% compostable flat pouches for their organic snack bars, and they insisted on no “plastic smell.” The first sample batch smelled like fermented corn (which makes sense, since many bio-resins are made from corn starch), and even after airing them out for a week, the scent was still noticeable. We switched them to a compostable plant-based resin that’s refined to remove most of the natural odor, and that worked—though it still has a fainter, earthier scent than standard plastic pouches, which is normal.
So what should you do if you receive flat pouches and notice a smell? First, don’t panic. Most of the time, it’s temporary. Open the boxes, take the pouches out, and air them out in a well-ventilated area for 24 to 48 hours. That’s enough time for any trapped residual odors from manufacturing to dissipate. If the smell is stronger after airing, test a small batch of pouches with a small amount of your product to see if the smell transfers to the inside or mixes with your goods. If it does, that’s when you need to check if the pouch is the right material for your product, or if the pouches were damaged in storage. And if you’re working with a reputable supplier like ours, you can always send back samples for testing—we’ll take them back, run them through our quality lab, and tell you exactly where the smell is coming from, no fine print.
At the end of the day, as a flat pouch supplier, our job isn’t just to make pouches that hold products—we make pouches that protect products, keep them fresh, and don’t ruin what’s inside. Smell is one of the easiest quality issues to catch, because it’s something people notice immediately, and we take it extremely seriously. We’ve built our business on solving small problems like this for our clients, whether that’s adjusting a material layer, updating a production step, or troubleshooting a storage issue.
Recyclable Packaging If you’re looking for flat pouches, whether for food, skincare, pet products, or anything else, and you have questions about odor testing, material compatibility, or low-odor options, reach out to our team to discuss your specific needs. We’ll send you free samples, walk you through our testing processes, and make sure your pouches are exactly what you need.
References
- European Food Safety Authority. (2022). "Volatile Organic Compounds in Food Contact Plastics: Risk Assessment for Consumer Products". EFSA Journal.
- American Society for Testing and Materials. (2021). "Standard Test Method for Odor and Taste Testing of Packaging Materials". ASTM International.
- Plastics Industry Association. (2020). "Layered Packaging Structures: Material Selection and Compatibility Guidelines".
- U.S. Food and Drug Administration. (2019). "Guidance for Industry: Food Contact Substances for Polyethylene Resins".
Shandong Lepu Digital Printing Co., Ltd.
Shandong Lepu Digital Printing Co., Ltd. is one of the most professional flat pouch manufacturers and suppliers in China, specialized in providing high quality customized service. We warmly welcome you to buy high-grade flat pouch made in China here from our factory.
Address: 500 meters north of the intersection of Huaihai 2nd Road and Xiwu Road, Junan County, Linyi City, Shandong Province
E-mail: sales01@lepupac.com
WebSite: https://www.lepupouch.com/
