Tidal flip flops are now
made w/ plants*
we put the planet first.

When we set out to create the world’s most comfortable flip flop in 2014, we carefully considered the material options. Our search concluded with polyurethane, a chemical compound that’s an incredibly comfortable and durable material. And while it served us well for the last 5 years the challenge was that polyurethane derives from fossil fuels. Knowing we could always improve, TIDAL soles are now formulated using a renewable plant-based material; castor seed extract.

Yes, we make flip flops that last you well beyond a single season and make them locally—two practices we believe help shape sustainable consumption. Yet we always wanted to do more by addressing our inherent dependence on oil, the raw material used to make polyurethane. So we went back to the drawing board and this is how we just became 13.11% better.

Our approach has always been progress, not perfection. For us, this is just the starting line. We’re on a path to renewability and we’re super excited to share how we got here and where we plan to go. So if you’re interested in geeking out with us … keep scrolling.

We Are Leading

We’re on the cutting edge of technology. Not just for flip flops, but for all footwear. Most midsoles in your sneakers, boots and sandals are made from non-renewable material. Until now, Tidals were too. In an innovative and forward thinking step, we reformulated polyurethane, transforming it from non-renewable to now include renewable matter, without losing any of its material benefits. We just went 13.11% further down a path that others haven’t thought to go down yet.

But, why make such a big deal about 13.11%? To us, 13.11% is the start of a journey to creating a fully renewable flip flop. That’s today, but tomorrow is a different story. Our goal is to improve, innovate and increase renewability in every pair of Tidals. Rather than waiting until we are 100%, we want to be transparent, share this process with you, and have you join us along for the ride.


Synthetic materials (i.e polyester, polyurethane and EVA) are made from fossil fuels. We knew entering the flip flop biz our Achilles’ heel by nature would be footwear’s reliance on fossil fuels. In an effort to break this dependence, we made the choice to introduce bio-based materials.

Extracting petroleum has an irreversible, harmful impact on the planet. Our reliance on it—from fuel to production needs to be addressed. A bio-based renewable resource (aka plants!) was the only choice. By moving away from a resource that is guaranteed to run out, we are setting ourselves up to build a business and contribute to an economy that is inherently more sustainable. Not to mention, our leafy green friends have a positive impact; producing oxygen to balance the carbon in our atmosphere. More plants can be sown, grown, harvested but there are a finite amount of fossil fuels left, all of which leave a toxic footprint on our planet.

Meet Castor

The castor plant is incredibly abundant, takes few resources to grow and has surprisingly limited modern-day usages. We seized this opportunity to innovate—making our soles more renewable in a way that hasn’t been widely commercially leveraged yet. With increasing renewability in mind we worked closely with longtime material suppliers Maremec, an innovative family-run business, to find the best, most viable option.

Enter: Castor, a curious, spiky pink plant that grows easily in very warm climates. Maremec ethically source castor through Acme Hardesty, an Indian grower with strident social compliance standards—ensuring farmers work in healthy and safe environments. Castor is one of the most environmentally friendly plant-based extracts. A fast grower—one plant can grow 6 to 15 feet in a season! Its seeds also deliver a high oil yield at 42% to 48%. Acme Hardesty is working to further advance this yield, improving water usage by collecting rainwater and intercropping. Castor’s commercial viability increases by the fact it has the highest and most stable viscosity of any vegetable oil. This versatile plant needs limited resources to grow—easily transforming with minimal impact from seed to foam to … VOILA(!) super comfy TIDAL flip flops.

Seed to Sole

A quick lesson in chemistry for all those wondering how exactly we take a prickly plant and transform it into comfy flip flop soles. Simply put, castor undergoes a chemical process moving it from a seed to an oil to a foam, which is then poured into our bespoke molds to create your Tidals.

To start, castor seeds are harvested and dried, which allows the hull to split open and expose the seed inside. Once the hull cracks, the seeds are removed. The cleaned seeds are cooked to harden the interior, which makes it easier to extract the oil. The seeds then move through a high-pressure continuous screw press. In a final step, the oil is degummed, removing toxins and stabilizing the oil to be made into foam.

Calling all chemists to the front of the class because this is where things get a little complicated. Transesterification is the chemical reaction that converts vegetable oils into polyols (a type of complex alcohol). Previously, we mixed ethylene and propylene oxide (fossil fuels) with a catalyst and UV additives to formulate our soles. In the newest iteration of this formula, we are replacing the 20% of the polyol in polyurethane foam with polyols from castor oil. The result: a formulation containing 13.11% renewable materials. In the end, it’s actually quite simple—we’re replacing the bad with good, moving our formulation forward from fossil fuels to renewable materials.

Same Comfort,
Now Renewable

Our favorite thing about our renewable formulation is that when you slip on a new pair, you’ll never be able to tell the difference. Translation: Tidals now made w/ plants* are just as comfy, bouncy and durable as our earlier formulations. Comfort was never something we were willing to compromise on. That’s why we dedicated endless hours and long days to guarantee our new renewable component wouldn’t mess with that blissful all-day comfort you’ve come to know and love with TIDAL.

Ok, So What’s Next?

Like we said, 13.11% is just the start. For now, castor seed oil replaces 13.11% of the polyols that go into our sole formulation. But that is just for today. We are right now exploring forward-thinking ways to significantly increase this percentage, as well as considering other bio-based materials that could potentially get TIDAL to 100% renewability sooner. As we strive for greatness, we are also looking into biodegradability—currently testing this formulation to see where our soles fall on this scale. We continue to work with scientists to consider innovations that will help us on the path toward biodegradation, with the goal for our soles to be 100% biodegradable as well. As you can tell, it’s a process, but we promise to always keep you up to speed.

Creating a solution-driven brand is as much about our community as it is about production, material and innovation. We hope you reach out, ask more questions about our process and hold us accountable. Email us at sustainibility@tidalnewyork.com to chat!