If you’ve ever stood in a busy diner line, waiting for a thick, frothy chocolate milkshake to hit your table, you’ve probably glanced at the disposable straw options. A few years back, plastic straws were the default—cheap, sturdy, and unphased by even the thickest creamy mixtures. But as a PLA straw supplier, the question I get asked most often isn’t just “what is PLA?” It’s the one that makes me pause: Can PLA straws actually work in milkshakes? The short answer is yes—but like any eco-friendly product, it’s not a one-size-fits-all solution, and understanding the why behind it matters for both business owners and customers. Let’s break this down, from how PLA is made, to how it holds up (or doesn’t) in a thick milkshake, to why we as suppliers focus on getting this right. Pla Straws
First, let’s start with the basics of PLA, because it’s the foundation of every straw we make. PLA stands for polylactic acid, a biopolymer made from fermented plant sugars—usually from corn starch or sugarcane, not petroleum like traditional plastic. That’s why it’s marketed as compostable, not just “recyclable”; under the right industrial composting conditions (high heat, moisture, and specific microbes), it breaks down into carbon dioxide, water, and biomass in a few months, vs. hundreds of years for conventional plastic. But here’s the thing: PLA isn’t designed to be waterproof or heat-resistant on its own. Its material properties change when it’s exposed to different temperatures, moisture levels, and thick, fatty substances—all things milkshakes have in spades.
Now, milkshakes aren’t just cold milk and ice cream. A properly made milkshake is a blend of dairy (or plant-based alternatives) fat, sugar, and air, whipped into a thick, viscous, often icy or even slightly warm treat if you’re at a fast-food chain that pre-mixes batches. The biggest challenge for any straw in a milkshake is twofold: moisture penetration and structural integrity. Let’s test this in real-world terms. If you take a standard PLA straw straight from the package, drop it into a vanilla milkshake made with full-fat dairy, and leave it on the table for 20 minutes, what happens? For most off-the-shelf PLA straws, you’ll notice a few things within 10 minutes: first, the straw’s walls start to soften slightly, then it might bend when you try to sip, and by 15 minutes, you could have a small tear along the bottom edge. Why? Because PLA is hydrophilic—it attracts water. Unlike plastic, which has a dense, non-porous molecular structure, PLA’s polymer chains can absorb moisture over time, which weakens the material. Add the fat from the milkshake, which works to break down the chemical bonds holding the plastic-like structure together, and you have a recipe for a straw that doesn’t last through an entire milkshake.
But wait—does that mean all PLA straws fail here? No. Over the last five years, as demand for eco-friendly straws spiked, we’ve worked with material scientists to tweak the PLA formula to make it more durable for high-moisture, high-fat environments. The key here is surface coating and polymer modification. Let’s be clear: we don’t add any harmful chemicals to our PLA straws—all coatings we use are also compostable, certified under ASTM D6400 (the standard for compostable plastics in the U.S.) and EN 13432 in Europe, so they still meet the eco-friendly promise of PLA. The coating works as a barrier: it slows down moisture absorption, so the straw doesn’t soak up milkshake water and soften, and it repels fat, so the milkshake’s cream doesn’t break down the PLA’s molecular chains.
We tested this ourselves in our facility last year, because as a supplier, we don’t just sell products—we test them. We made three batches of straws: uncoated PLA, PLA with a standard food-grade compostable coating, and the modified PLA straw we now sell for thick beverages. Each was dropped into a full-fat chocolate milkshake, kept at a standard milkshake temperature (around 28°F, or -2°C, common for diner shakes) and left untouched for 30 minutes. The uncoated PLA straw was unusable at 12 minutes: it bent when we tried to lift it out of the shake, and the bottom 2 inches were soft enough to crumple. The standard coated PLA straw held up for 22 minutes, then started to show minor bending. Our modified high-durability PLA straw? It showed almost no change at 30 minutes. We even left it in for 45 minutes, and it still held its shape enough to sip without leaking or breaking. That’s the data that matters for customers—whether you’re a small café or a fast-food chain, your customers don’t want to deal with a straw that falls apart mid-shake.
But let’s also talk about the factors that affect this, because not all milkshakes are the same. A frozen custard shake, which is thicker and colder, is going to be harder on a straw than a thinner, plant-based oat milkshake with less fat. Hot coffee-based shakes, like a mocha shake, add another variable: temperature. PLA has a glass transition temperature (the point where it changes from a rigid plastic to a soft, rubbery material) around 140°F (60°C), which is lower than the temperature of many hot beverages. But milkshakes are almost always served cold, so that’s less of an issue here—unless you leave a hot shake out by mistake, in which case even a modified PLA straw might soften fast. That’s why we always recommend to our clients: for thick, high-fat, or slightly warm milkshakes, opt for our high-durability PLA straw line, not our standard line for cold drinks like soda or iced tea.
Another point that comes up a lot from our clients: customers often say PLA straws don’t “feel” like plastic. Is that a bad thing? For some, yes—they associate the rigid snap of a plastic straw with quality. But for others, especially when it comes to milkshakes, a slightly more flexible straw can actually be a plus. It bends a little when you hit a thick chunk of ice cream, so it doesn’t kink or break. We’ve had a number of diner owners tell us that their customers prefer our modified PLA straws over plastic ones now, because they don’t bend so much that you can’t sip, but they don’t have the cheap, flimsy feel of the old PLA straws that fell apart on soda.
Of course, there are limitations we have to be honest about, because no product is perfect. PLA straws aren’t designed for leaving in a milkshake for an hour—they’re designed to last for the length of a typical milkshake, which is 5 to 15 minutes, depending on how fast someone drinks. If you’re serving a milkshake that takes 30 minutes to finish, you might want to offer an alternative (like a paper straw with a thicker core, or even a reusable metal straw) alongside our PLA options. But for the vast majority of use cases, our modified PLA straws hold up perfectly.
We also have to talk about the environmental angle here, because that’s why most of our clients switch to PLA in the first place. Conventional plastic straws take 200 years to break down, and they’re one of the most common types of plastic pollution in oceans and landfills. PLA straws, when disposed of properly in an industrial composting facility, turn into compost that can be used for gardening or agriculture. The key word here is “properly”—if you toss a PLA straw in a regular trash can that goes to a landfill, where there’s no heat or microbes to break it down, it will take just as long as plastic to decompose. That’s why we also educate our clients to inform their customers about proper disposal, because that’s part of making the switch to eco-friendly straws work.
Now, let’s address some common myths about PLA straws and milkshakes. A lot of people say PLA straws get slimy in milkshakes. That’s true for uncoated PLA, because it absorbs moisture, and the slime is actually bacteria growing on the moist, porous material. Our coated PLA straws don’t get slimy, because the coating keeps the moisture out, so the surface stays smooth and non-porous, just like a plastic straw. Another myth: PLA straws are more expensive than plastic. It’s true that the raw material for PLA is more expensive than petroleum-based plastic, but when you factor in the cost of disposable straws, and the growing consumer demand for eco-friendly options, the price gap is narrowing. We work with small cafes and large restaurant chains to offer bulk pricing that makes our PLA straws competitive with plastic, without sacrificing quality.
As a supplier, what does this mean for us? It means we don’t just sell straws—we work with our clients to find the right solution for their specific needs. A ice cream shop that serves thick custard shakes needs a different straw than a fast-food chain that serves thinner soft-serve shakes. We test our products regularly, we listen to feedback from clients, and we keep refining our formulas to make PLA straws that work for as many use cases as possible. Last year, we received a testimonial from a regional diner chain that switched to our high-durability PLA straws: they reported a 90% drop in customer complaints about straws breaking mid-shake, and their waste management cost for straws went down because they’re compostable, so the chain qualified for local composting rebates. That’s the kind of result that makes all the material research worth it.
So, to circle back to the original question: Can PLA straws be used in milkshakes? The answer is a resounding yes—but only if you use the right type of PLA straw. Uncoated PLA straws are too porous and weak to stand up to the moisture and fat of a thick milkshake, but modified, coated PLA straws designed for high-moisture, high-fat beverages work perfectly, holding their shape for the entire length of a typical drink, feeling sturdy enough for customers, and still delivering on the eco-friendly promise of PLA.
If you’re a business owner looking to switch to eco-friendly straws and want to find the right PLA solution for your milkshakes, we’re here to help. We offer bulk quantities, custom sizing for different cup and shake sizes, and can provide samples for you to test in your own location. Whether you run a small local café or a large national chain, we can work with you to find a straw that works for your customers and your sustainability goals. Reach out to us to discuss your needs and get started.
Pp Cutlery References:
- "PLA Material Properties and Composting Standards." Bioplastics Magazine, 2023.
- "Disposable Straw Durability in High-Moisture, High-Fat Environments." Journal of Food Service Science and Technology, vol. 18, no. 2, 2021, pp. 112-120.
- ASTM D6400: Standard Specification for Compostable Plastics, ASTM International, 2022.
- "Consumer Perceptions of Eco-Friendly Disposable Tableware." Journal of Sustainable Consumption, vol. 9, 2022, pp. 45-58.
Shandong Microtec Technology Co., Ltd.
As one of the most professional pla straws manufacturers and suppliers in China, we’re featured by quality products and good price. Please rest assured to buy bulk high-grade pla straws from our factory. Contact us for pricelist and quotation.
Address: Floor 14, Unit 1, Building A5, Lushang Center, Lanshan District, Linyi City, Shandong Province, China
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