Chart of the week: vanilla is more valuable than silver

Vanilla is one of the world's most popular flavours, but a dear one: a supply squeeze over the past few years has propelled prices to record highs. Five years ago, the price of 1kg of vanilla was $20. In 2018, it briefly became more expensive than silver, reaching a peak of $600 a kilo, before falling back. Most of the world's natural vanilla comes from Madagascar, so events on the island affect the global industry.

In March 2017, Cyclone Enawo struck the island and destroyed much of the year's vanilla pod crop. Two of the largest vanilla-producing regions were affected. Because it takes three to four years for a new plant to bear vanilla pods, farmers have been struggling to meet demand ever since. No wonder prices have risen so sharply.