Many brands provide an overly scientific and confusing answer or simply baffle you in terms of marketing blurb. One fact to set straight is that memory foams only memory is to return to its original position once the person on it gets off it. It won’t remember your body shape once you get off it! It would be more accurate to call memory foam ‘heat reactive foam’ but that doesn’t sound nearly as sexy does it?
Memory foam is a man-made foam which has a high density and viscosity compared to other foams. Memory foam has an open cell structure which allows it to change shape with heat and mould. This type of foam is typically heat sensitive, which means it reacts to heat making it softer and more pliable, so when someone lies on it, their body warmth allows the memory foam to mould to their body shape. I say typically because there are exceptions in the lower density memory foams that don’t rely on heat to mould to the person on it. I will discuss this in our Hybrid foams section.
Memory foam comes in a huge variety of densities and qualities, the best analogy is to compare it to cushions. You can buy a cheap cushion for a couple of pounds or an expensive foam cushion and instantly feel the difference, whereas one quickly loses its shape and sags the other retains its shape much longer. When discussing memory foam you must remember that there is no one uniform type of ‘memory foam’ there are hundreds of types.
Density and hardness are quoted according to in-house test methods based on BS EN ISO 845 and BS EN ISO 2439 respectively.