Composite Sushi Roll?

Hokkaido University have recently come up with a new material that is 5x stronger than carbon steel. They did this by combining hydrogel (a wobbly jelly like substance) and glass fibers, creating a composite material.

What is a composite material?

Composite material is a blend of two (or more) materials, where the materials work together to each give the new material their type of characteristics that they are good at.

Think of a sushi roll as a composite material. The outer seaweed layer stops the rice from spilling out everywhere. The rice stops the seaweed getting wet, while tightly binding the middle ingredients together. The filling, especially if you got a vegetarian one, gives the sushi a hard core to stay up straight while we chomp away.

Take away any one of these materials, you will end up with a sushi roll that you can’t eat without a big mess:

  • No seaweed – rice spills everywhere at the pressure from being picked up (Ok this doesn’t apply if you are a sushi master.)
  • No rice – sloppy wrap that will tear from moisture and you end up with a soggy mess of vegetable
  • No filling – a roll that will flop over at first sign of wobble

Next time you look at a sushi roll, think of the ingenious composite that is your lunch.

What about Nigiris?

Ok… so how does Nigiris (a cube of sushi with filling on top) stay together without the seaweed? Nigiris are often made with a higher level of stickiness in the rice. The stickiness means that you do not need to have a seaweed wrapper. The stickiness of the rice makes the seaweed’s characteristic of holding the rice together redundant.

This emulates an evolution of composite in real life. If one material of a composite gets more desirable characteristics as time goes on, the composite can become simpler (usually also cheaper) to manufacture. Eventually, some composites become obsolete when another material is discovered that replaces all the useful characteristics of the original composite. (Newspaper as wall insulation, anyone?)


  1. I’ve never thought about sushi rolls that way! Thanks for this interesting post. Will be showing it to my daughter.

Comments are closed.