Get ready to nuke your packed lunch: a new era in microwave cookery is around the corner. As well as portable ovens you can stick in a backpack, electronics will enable appliances that detect when their contents are thawed or risk boiling over, and smart ovens which will cook multiple items at different rates simultaneously.
Conventional microwave ovens use a cavity magnetron, a vacuum tube developed for radar during the second world war. Magnetrons are heavy and not efficient at generating microwaves. They may also create hotspots, a problem not totally solved by rotating the oven’s contents on a turntable.
Laterally diffused metal oxide semiconductor (LDMOS) microwave sources promise to change that. Similar to those in cellphone towers and microwave communication systems, they are now being worked on by firms such as NXP, based in Eindhoven, the Netherlands. “The underlying technology has been here a long time; we’re making changes to make it more specific and suited for consumer cooking appliances,” says NXP’s Paul Hart.
The compact size and high efficiency of the source makes portable microwave cookers possible, such as the 1.5-kilogram Adventurer from Wayv, a company based in Hertford, UK. The Adventurer looks like a large thermos flask, and its NXP source can heat up to 500 millilitres of food or drink in cycles of up to 5 minutes. The rechargeable lithium-ion battery is good for six cycles on one charge.
The Adventurer raised £150,000 in less than 19 hours on the crowdfunding site CrowdCube in 2014. It will be launched first in the US early next year and will cost about $199. Wayv envisages it being used by campers and hikers, as well as the military and first responders. Unlike with camp stoves, there is no smoke or danger of carbon monoxide poisoning.
Chris Brock, director of the London Food Centre at London South Bank University, says that the Adventurer’s usefulness for camping or hiking is limited due to the number of cycles that the battery allows — food and drink for one person would require two or three cycles per meal. But he suggests the Adventurer could also be used in experiments that require heating in the field.
NXP are also working on their own sophisticated ovens. The Sage “smart oven” (pictured below) incorporates multiple microwave sources as well as convection heating. Having multiple sources allows Sage to sense individual items and direct microwaves to cook them differently.
The technology in the Sage can sense changes in the electrical resistance of the contents, which alters as ice changes to water, or water to steam. That means it can defrost a meal without cooking it, or stop just as your soup boils over.
For example, the firm claims Sage could cook chicken, potatoes and peas perfectly on the same plate despite their different heating requirements. And it says that Sage can also cook or defrost complex items such as a sponge cake with a cream filling, heating each component evenly.
It will also enable novel types of takeaway or instant meal optimised for “smart cooking”.
“This is just the tip of the iceberg,” says Hart.