The flow of spices from one part of the world to another sparked the need to develop extensive infrastructure on land and by the coast, says Marijke van der Veen, emeritus professor of archaeology at the University of Leicester. This began in the Roman period, extending through the middle ages. 

“This is very much the start of globalisation,” says Van Der Veen. “We see that even more significantly in the medieval period.”

The result was a lasting change to people’s diets in Europe, which became a lot less bland and monotonous. But more importantly, spices became another way to define what it meant to be wealthy and powerful. This came with a profound social, emotional and economic impact in Europe, says Van Der Veen. 

“Spices give the elites opportunity for extravagant display,” says Van Der Veen. “And it emphasises to everybody else that it is out of reach.” 

As a result, the hunger for spices went well beyond their aromatic flavour. While spices had been consumed in Asia for most likely as long as there had been people living there, in Europe they became a new symbol of high social status. 

“The consequences of these trivial products – trivial in that you don't need them for nutrition – are cataclysmic,” says Paul Freedman, a historian at Yale University. “They were the first goods to have such dramatic and unanticipated consequences.” 

Those consequences included the colonisation of the New World, after Christopher Columbus took a wrong turn in search of spices, heading westward instead of eastward to reach the Americas. 

Compared with its turbulent beginnings, the nature of the spice trade is almost unrecognisable today. Spices are now accessible and ubiquitous, found everywhere from supermarket aisles, corner shops and take-aways to fine-dining restaurants. Where sailing Da Gama’s sea route took months, spices can now be flown across continents in a matter of hours. 

But some things have remained constant throughout the centuries, including the place that has remained the heart of the trade – India.

India’s history as a spice-producing nation is largely down to its climate, which is varied and ideal for growing a range of different spice crops. For example, turmeric, one increasingly valuable spice, grows well in India’s tropical, high-rainfall regions, whereas spices such as cumin flourish in cooler and drier subtropical areas. 

Many spice farms in India are historically small and family-run. But fluctuations in the value of spices on the open market can make farmers’ incomes more precarious. 

“Some of the biggest pressures on the industry are around climate change – more extreme weather patterns, flooding, hurricanes, droughts in different parts of the world,” says Anne Touboulic, a global food supply chain researcher at the Nottingham University Business School. “That will affect rural crop production, which would in turn have an effect on how much spice can be supplied, and then on prices.”

Many of the challenges for spice growers are shared by farmers of other crops. Overuse of nitrogen fertilisers, water shortages and the loss of pollinating insects. But combined with the high price of spice crops, these pressures on supply can have a knock-on effect. 

Outside India, one example of this is Madagascan vanilla. Natural vanilla is one of the most expensive spices in the world, with ripe, high-quality vanilla exceeding the price of silver to become worth more than $600 (£445) per kilo in the summer of 2018. A cyclone in 2017 in Madagascar, which produces the majority of the world’s vanilla, hit the vanilla crop hard and caused prices to surge. 

“The price of vanilla has risen because it is in high demand, and it is becoming a lot rarer because of extreme weather in Madagascar,” says Touboulic. “What that means is there are a lot of farmers going into vanilla to produce the bean and earn a living.”

But to grow the crop you need space, and the land to grow the vanilla has to come from somewhere. 

“There are beautiful forests in Madagascar, home to all sorts of interesting ecosystems,” says Touboulic. “You see them being cut down.” 

As well as being devastating for wildlife, including several endangered species, deforestation threatens future production of vanilla. The forests of Madagascar provide the right amount of rainfall, humidity and nutrients in the soil for the vanilla plants to grow. Disturbing Madagascar’s delicate ecosystem also disrupts the finely-balanced conditions needed for vanilla growing in the first place. 

“You can't blame the vanilla growers for doing it,” says Touboulic. “All they want to do is survive.”

When demand rises, it opens the door to as many challenges as it does opportunities. New technologies are being used to find innovative ways to make the spice trade more transparent, in a market increasingly concerned with quality and provenance. 

“Spices are incredibly high-value commodities for ingredients – they trade for huge amounts of money,” says Chris Elliott, a researcher at the Institute for Global Food Security at Queen’s University Belfast. “Often, with such a high-value commodity, a massive amount of cheating goes on.”

That cheating can take different forms. Unscrupulous traders find many ways to cut the spice, adulterating it with a bulking agent or blending with something else. “It’s just general non-edible rubbish,” says Elliott. Adding something of low or no value could boost the spice by a volume of 20-30%. 

Another common cheat is to spike the spice with substances that give the impression of higher quality – such as food dyes to make the product take on a richer, more appealing colour. Sometimes these are industrial dyes, not intended for human consumption. There are hundreds of cases each year of valuable spices like paprika and saffron being found to be tainted with unauthorised harmful substances such as the dyes Sudan I and Para red.

It’s hard to document the scale of cheating in the spice industry, says Elliott. But looking at the high-value herb oregano, his team in Belfast found in one study that up to 40% of batches were fake. 

But food-fraud detection is catching up with the cheats. Each spice has a “molecular fingerprint” that can be analysed using infrared spectroscopy. The fingerprint is made up of several thousand different molecules that are present in characteristic proportions. Any bulking agent or other additive will show up as an anomaly in the fingerprint. 

Traditionally, samples would be shipped from a factory or shop to a laboratory like Elliott’s. But it can take around two weeks from sampling to results. 

“In a supply chain, two weeks is a lifetime. That spice can be in 56 different countries by then,” says Elliott. 

Scanners that can be fitted to a smartphone are one solution that Elliott and his team are trialling. This way, a quick scan of the powder in front of you can give a green light to assure authenticity, or a red light to show that something is amiss.

“A lot of spice companies are interested. They want to show that they don’t have any cheating going on,” says Elliot. “If they can adopt the technology they can add a to their product – to show it has been scientifically tested to be pure.”