Under the Sheets: The Continuous Innovation Behind the Casper Mattress
When the Casper mattress launched in April of 2014, we sold through our entire inventory in just hours. The mattress was quickly named best invention by TIME Magazine, and grew a cult following of happy sleepers.
A lot of people know Casper for disrupting the mattress industry with our direct-to-consumer model, sleek design, award-winning customer support, and that iconic blue-striped box delivered to your door.
But what many don’t know is the engineering and science that has gone into the Casper mattress over the last two and a half years. Because while the mattress has been universally comfortable since day one, we’ve never stopped at creating and improving the most perfect night of sleep possible.
We spoke with the brains behind Casper’s obsessively engineered mattress — Casper’s Chief Product Officer and Co-founder, Jeff Chapin.
Jeff, tell us about the continuous innovation your team of 30 scientists, designers, and researchers has spent the last 800+ days (and nights) testing and implementing.
Jeff: Our team has made a series of improvements based on ad nauseum testing in our engineering lab. One change we made, as a result, is how the top layer of the mattress, an open-cell foam, is manufactured so it has better consistency and tighter tolerances.
What this means for the mattress: Improved support (for proper sleeping posture and spinal alignment), great airflow (for sleeping cool) and the right amount of bounce (so you can easily change positions and better enjoy indoor sports).
Jeff: We partnered with a polymer chemist to lower the transition glass temperature (Tg) of our visco memory foam while maintaining durability. We switched to a new proprietary memory foam with a Tg of about 40-degrees Fahrenheit. Our new visco memory foam stays supple at far lower temperatures than other mattresses, maintaining the Casper feel at a much wider temperature band. Most visco foams on the market have a Tg of around 60F — meaning that below 60F, the foam gets hard and would not be comfortable to sleep on. As such, most companies want a Tg as low as possible. The difficulty is that foam becomes fragile if you push the Tg too low, so you end up sacrificing durability for a low Tg. The “biggest memory foam mattress manufacturer” goes the opposite direction on Tg and set their visco Tg at about 80F. This is why their mattresses are always hard and then ‘melt’ when you lay on them making it difficult to move around.
What this means for the mattress: The right amount of sink in all climates. Mitigating the key downsides of memory foam (sleeping hot, getting stuck in a body impression cavity and having no ‘life’ to the mattress) while continuing to provide pressure relief (to reduce sore spots and allow good blood flow) and providing motion isolation (so you don’t feel your partner — or dog —move).
Jeff: We changed the chemistry of the base foam at the molecular level. We test our foams day in and day out to understand the expected softening and keep it below a human-perceptible level. The measurement of foam firmness used in the industry is Indentation Load Deflection (ILD). The ILD test is a standardized procedure that involves putting a foam sample in a test apparatus that presses down on the foam. The higher the Support Factor, the more the foam pushes back on you as you push further into it. Support Factor is more tied to chemistry than density — two different foams of the same density can have wildly different support factors. Instead, density is more indicative of the expected life of a foam. The higher the foam density, the longer they’ll retain structural integrity — minimizing softening.
What this means for the mattress: Improved long-term durability while retaining the best level of support.
Jeff: One of the most significant improvements we’ve made is the addition of a fourth transitional layer between the open-cell and memory foam and our firmer base foam. As way of history, our original mattress was comprised of three layers: 1.5″ of our open-cell foam, over 1.5″ of visco/memory foam, over a polyurethane base foam. As you push through the full mattress and compress the top foam layer, you move from the open-cell into the visco memory foam and then into the base foam layer. This feel as you push through the mattress is colloquially called Ride. Generally, you want as smooth a Ride as possible. Any inflection points or step changes in firmness can affect comfort, especially for larger weight people (who will push in more) and for when people are on their sides (when their hips and shoulders push deeper into the mattress). We ran a series of tests on both the 3-layer and 4-layer mattress. The new 4-layer mattress proved to have a smoother Ride.
What this means for the mattress: This softens the mattress at its deepest layers to relieve even the slightest pressure. This is especially important for side sleepers or when sitting up in bed. The added layer has a high support factor and further improves spinal alignment.
And these continuous improvements to the Casper mattress have not gone unnoticed. The most credible, unbiased reviews source just rated Casper the top memory foam mattress.