Ever wondered where the natural latex on certain mattresses comes from? Natural latex is a milky sap that can be harvested from rubber trees like Hevea brasiliensis.
A government publication from 1990 claims there are more than 12,000 plant species that yield latex containing natural rubber, though in many of those species the natural rubber is not suitable for commercial use. Suitable latex that contains rubber can be used to make items like mattresses, balloons, and gloves.
Rubber trees are native to South America but were imported to countries around the world in the 19th century. In the wild, they can reach up to 130 feet in height, and live for 100 years. According to The Rainforest Alliance, rubber trees do best in “low-altitude moist forests, wetlands, riparian zones, forest gaps, and disturbed areas.”
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To harvest latex from trees, you need to “tap” them — a process similar to tapping trees for maple syrup. The Alliance Rubber Company explains: “To ‘tap’ the substance, rubber harvesters cut a wedge in the bark. They must reach the latex without cutting into the sap vessels. After workers make a cut, latex oozes out and collects in a container attached to the tree.
Tapping takes place every other day and each tapping yields about 2 ounces (56 grams) of the substance. After tapping, the cut dries, and latex stops flowing in an hour or two.” The tapping process should not harm trees when conducted properly. According to Alliance, you can tap trees starting when they are six years old and continue to tap them for up to 28 years.
So, what exactly is the point of having latex in your mattress — and how does it get there? Latex is used to create latex foam, which helps make mattresses springy and comfortable. There are two processes that turn latex into foam: The Dunlop method, or the Talalay method. Both methods involve washing the latex foam to remove impurities and additives, but otherwise there are a few difference between the two processes.
“Dunlop is the name for the original process – named after the inventor – which basically heats up foamed liquid latex with the addition of sulphur, turning it into a flexible, resilient block of foam (Vulcanization),” latex expert Andrea Karsten explained in an interview. “The Talalay process is based on the Dunlop process but adds a freeze/vacuum step before vulcanization which results in a more open and interconnected latex structure.” Karsten further explained: “Dunlop tends to feel more solid and offers very stable support, whereas Talalay can be made in softer grades and tends to feel softer and more yielding.”
Fans of natural latex bedding products note that natural latex is resistant to mildew, mold, dust mites, and bacteria. If you’re in the market for a mattress made with natural latex, be sure to research whether the product contains 100 percent natural latex or a blend of natural and synthetic latex. If you’re worried about allergies, make sure to read our latex mattress allergies article.