Not yet. At the moment, having customers mail back used capsules for cleaning and refilling would create more carbon emissions (from shipping and sterilization) than simply using new recyclable capsules. Instead, we encourage you to recycle the capsules locally. We agree that reusing packaging is an ideal goal (reusable solutions are generally the most eco-friendly in the long run), and we plan to offer a take-back or reuse program once the overall math turns positive. As soon as we can ensure a reuse system would actually reduce emissions and waste, we will implement it.

Most bioplastics (like PLA made from corn) only break down under specific high-temperature composting conditions. In a regular landfill or the open environment, they remain largely intact. One study found that only about 1% of a PLA bioplastic decomposed after 100 years. If not properly composted, biodegradable plastics can still fragment into microplastics as they slowly degrade. In short, a plant-based plastic isn't automatically eco-friendly if it can't fully biodegrade in real-world conditions. We chose a fully recyclable, stable material (polypropylene) and offset its use with our 2:1 removal pledge to ensure a net-negative plastic impact.

No, polypropylene (PP) is known for its chemical stability and does not readily shed fragments under normal conditions. Microplastics tend to be generated when plastics are exposed to extreme conditions like prolonged UV, high heat, or intense mechanical stress. Our capsules are filled and used at room temperature without harsh agitation.

Stack's capsules are BPA-free and contain no harmful plasticizers. Polypropylene by nature does not use Bisphenol-A (BPA) in its production, unlike some polycarbonate or PVC plastics. In fact, polypropylene is an inert, food-safe material and it's widely approved for long-term food and medical contact and does not leach toxic chemicals. With our medical-grade polypropylene you won't need to worry about BPA, phthalates, or other concerning additives in the capsules.

We are continuously researching ways to further reduce waste. This includes testing new sustainable materials and monitoring emerging innovations (for example, truly biodegradable polymers that could break down completely without leaving microplastic residue. We're also evaluating refill or bulk-delivery systems that could eliminate single-use capsules. Any change will be implemented only once we find a solution that maintains product safety and quality while genuinely lowering the environmental impact (rather than just shifting the impact elsewhere). When a lower-impact, food-safe option proves viable, we will adopt it.