Steel is not an obvious choice for microwaveable packaging. But new, ductile grades and clear design parameters mean this could become a growth area for such alloys.
Many consumers wrongly assume that metal containers are incompatible with microwaves, says APEAL, the Association of European Producers of Steel for Packaging. But in fact, the last 10 years or so have seen the advent of ovens designed to avoid the problem of arcing.
New pack design guidance means that cans are able not only to avoid these problems, but also to provide more consistent heating than other materials. According to Charles Reuland, consultant at APEAL, microwaveable steel cans should have a maximum height of 3.5cm and diameter of 10cm.
The type of deep-drawn two-piece aluminium cans traditionally associated with beverage markets is increasingly being used in food applications around Europe. In conjunction with more ductile steel grades which have emerged over the last couple of years, this technology is now being used to produce smaller, more sophisticated shapes.
Future steel designs for the microwave are likely to combine insulating polymer coatings and easy-open lidding, says APEAL. They may also require a substantial consumer education campaign.