BBB GUIDE: All about latex
All about latex
Latex is considered one of the highest quality mattress components
Latex is a soft yet durable material derived from the sap of the Hevea brasiliensis, more commonly known as the rubber tree. The latex used in mattresses is usually a blended composite of natural latex (or NR) latex and synthetic (or SBR) latex, which is made of petroleum-based plasticizers and other petrochemicals. Mattresses that do not contain any synthetic materials, pesticides, herbicides or other manmade components are considered 100% organic and can be classified as such by the U.S. Department of Agriculture (USDA). This label is different from 100% natural latex, which may contain a small percentage of synthetic ingredients.
The ratio of NR to SBR latex in a comfort layer often correlates with both the price and overall quality of a mattress. Models with higher amounts of NR latex are more resilient and comfortable for sleeping, and thus tend to be more expensive.
Two different processes are used to produce latex. The Dunlop process (used for more than 80 years) requires the rubber tree sap to be stirred, molded and steam-baked, causing natural sediment to collect at the bottom. The result is latex that is dense, heavier and more sturdy. In contrast, the relatively new Talalay process involves placing the molded sap in a vacuum-sealed chamber, where it is deprived of air, frozen and finally baked. Compared to Dunlop foams, Talalay latex has a more homogenous consistency, making it softer and bouncier.
You can test the softness or firmness of a latex mattress by measuring the impression load deflection, or ILD; this term may be used interchangeably with impression force deflection, or IFD. To measure ILD, set a circular metal disk with a 1-foot diameter onto a section of latex that is roughly four inches thick. The ILD measurement will be the amount of load (weight) or force needed to compress the foam by 25%. ILD ratings range from ‘firm’ (high) to ‘soft’ (low), and are expressed in numerical measurements. ILD should not be confused with mattress density, which is an object’s mass divided by its volume; density measures mattress foam qualities like durability and support, and is typically used to evaluate polyfoam mattresses (see next section).
The following table looks at the general ILD rating categories for latex mattresses. Please note that some numerical ILD measurements aren’t listed on the table because they are considered ‘middle ground’ ratings between two categories. A latex mattress with an ILD of 28, for instance, is considered too firm for the ‘medium’ designation and too soft for the ‘medium-firm’ designation. Generally, Talalay latex will usually have a lower ILD rating than Dunlop foam.
|Category||ILD Measurement||Foam Characteristics|
|Soft||19-21||Mattress sinks considerably beneath most sleepers|
|Medium||24-26||Balances softness and firmness to a fairly even degree|
|Medium-Firm||29-31||Firm support with almost no sinking|
|Firm||34-36||Completely firm with no sinking whatsoever|
Latex is considered a high-quality comfort layer material because it will conform around your hips, shoulders and contours. This alleviates pressure points and supports your spinal alignment. This is especially beneficial for people with chronic back and joint pain, as well as side sleepers, who need more cushioning in their midsection. And due to the natural durability of latex, the material will offer proper support and comfort for years ― more than a decade, in some cases. In latex with a low ILD, you may need to continually rotate the mattress in order to restore your sleep surface to its original shape.
Motion isolation is another property of many latex mattresses. This term (also called motion transfer) refers to how much movement can be detected from one side of the mattress to the other. If your partner tosses and turns in their sleep, then sleeping on a mattress designed for motion isolation means you won’t be able to feel their movement from your side of the bed.
The smell of latex is also considered a perk by many users. Some mattress materials are prone to off-gassing, a reaction that occurs after the breakdown of substances called volatile organic compounds, or VOCs. Off-gassing produces a pungent, often unpleasant odor. Synthetic latex is known to produce some off-gassing, while organic and natural latex produces little to no off-gassing. Due to the low VOC levels, natural latex often receives green certification from third-party eco-labels like Oeko-Tex 100 and Eco Institut, as well as industry-oriented eco-labels like CertiPUR-US® certification (see the next section for more information about these certifications).
However, there are some known drawbacks to latex. One is poor heat retention; many report that latex sleeps hot, causing discomfort during the night―although natural and organic latex is considered more breathable. Cost may also be an issue for some mattress buyers, since mattresses with latex comfort layers tend to carry the heftiest price tags. Expect to pay at least $900 to $1,200, although the average latex model will cost roughly $2,000.
If you are interested in buying a mattress with a latex comfort layer, here are a few questions to ask before finalizing your purchase:
- What is the ratio of natural to synthetic latex? The amount of natural latex will usually dictate the comfort, lifespan and price of the mattress. The ratio also indicates the likeliness of off-gassing, since organic and natural latex causes less off-gassing than synthetic latex.
- Which process was used to produce the latex? The Dunlop process will produce a heavier and firmer comfort layer, while the Talalay process will yield a softer comfort layer.
- What is the ILD rating? Remember: the higher the ILD, the firmer the mattress.