Spice: Why some of us like it hot

Piles of spices in market (Credit: Getty Images)

Human beings around the world delight in fiery foods. Thai, Mexican, Chinese, Indian, Ethiopian – the cuisines that can take the roof off your mouth are numerous and flavourful.

Ranking the world’s most spicy peppers and comparing the most awe-inducing dishes is a common pastime, even if, past a certain point, the distinctions are somewhat moot. Who can say, subjectively speaking, that one Indian restaurant’s Widower Phaal, made while wearing goggles with chilis that rank about 1,000,000 on the Scoville Scale – an international measurement of pungency – is necessarily a fierier experience than the notorious Korean Suicide Burrito?

There’s plenty of burn to go around: more common dishes include vindaloo with ghost peppers and hot pot from Sichuan, where you must part a swarm of chillis bobbing in a sea of broth to fish out tender, fiery morsels of meats and vegetables.

As you savour these intense tastes, however, you may wonder, why do some cuisines compete for the title of spicy champion, while others feature barely the hint of a burn?

This is a question that has intrigued anthropologists and food historians for some time. Indeed, it’s a curious truth that places with warm climates do seem to have a heavier preponderance of hot and spicy dishes. That may have something to do with the fact that some spices have antimicrobial properties, studies have found.

Chilli pepper and powder (Credit: Getty Images)

Chillis pack fierce heat but also antimicrobial agents that could have been useful in the days before refrigeration (Credit: Getty Images)

In one survey of cookbooks from around the world, researchers note: “As mean annual temperatures (an indicator of relative spoilage rates of unrefrigerated foods) increased, the proportion of recipes containing spices, number of spices per recipe, total number of spices used, and use of the most potent antibacterial spices all increased.” In hot places, where before refrigeration food would have gone off very quickly, spices might have helped things keep a bit longer – or at least rendered them more palatable.

It’s also been suggested that because spicy food makes most people sweat, it might help us to cool off in hot parts of the world. The evaporative cooling effect that happens when we perspire is indeed useful in maintaining a body’s heat balance. In a very humid climate, though, it doesn’t matter how much you sweat: that evaporation won’t come to your rescue because there’s already too much moisture in the air. One study of people who drank hot water after exercise showed that they did cool down slightly more than those who drank cold water, but only in situations with low humidity. Thailand in August, that ain’t.

But spice is hardly limited to the tropics. While chilli peppers are originally from the Americas, this particular kind of heat grew widespread in the 15th and 16th Centuries, travelling with European traders. Other spices – not spicy in the same way as peppers, perhaps, but still strongly flavoured and bringing an extra oomph to a dish – had been circulating in Europe for centuries, with ginger, black pepper, and cinnamon brought in from the east.

As spice prices plummeted in Europe in the 1600s, and it became easier for just anyone to lace their food with them, tastemakers fell out of love with them

Heavily spiced dishes were the darlings of many cuisines we currently don’t think of for their zing. Numerous recipes in one 18th-Century British cookery book include potent doses of mace, cloves, and nutmeg, for instance. What happened?

Well, one possibility is that it became a bit uncouth to like quite so many flavours in one’s food, as Maanvi Singh has written over at The Salt. What we now consider classic European cuisine has a tendency to focus on pairing like flavours with like, rather than bringing in a riot of strong, contrasting ones. That may be because, as spice prices plummeted in Europe in the 1600s and it became easier for just anyone to lace their food with them, tastemakers fell out of love with them.

Shifting the goalposts for high-end food, they began to emphasise dishes where the focus was the purest essence of the basic ingredients, combined with flavours that served to bring that out. In a word – it may have been snobbery, Singh writes, that erased the thrill of spice from many European palates.

Nutmeg (Credit: Getty Images)

Many European cuisines used to be heavily spiced with ingredients such as nutmeg (Credit: Getty Images)

Indeed, the role of human culture in determining whether spice is hot or not cannot be underestimated. Like all animals, we use taste as a way to determine what’s safe to eat, and once we get used to certain flavors signalling the familiar, we like them all the more. It would not be surprising if some people, having acclimated to chillis, began to prefer them over the absence of chillis.

Today, we have our own reasons for eating spicy foods, and they may have more to do with adrenaline than social status or sheer flavour, per se. The physiological reaction to peppers, as we’ve discussed here before, is the result of temperature sensors in the mouth being activated. Your body responds as if you had burned it, causing you to sweat and flush, and in extreme cases vomit.

The thrill of triggering this intense experience without (usually) any long-term effects is thought to be part of the attraction – as well as, for some chilli fiends, the bragging rights.

Antimicrobial qualities and body temperature regulation are probably not on the list of possible draws today – something to ponder, and thank your lucky stars for, as you wait for your next curry.

Asteroid impact plunged dinosaurs into catastrophic ‘winter’

Artwork impactImage copyright   BARCROFT PRODUCTIONS/BBC
Image captionArtwork: The impact hit with the energy equivalent to 10 billion Hiroshima bombs

Scientists say they now have a much clearer picture of the climate catastrophe that followed the asteroid impact on Earth 66 million years ago.

The event is blamed for the demise of three-quarters of plant and animal species, including the dinosaurs.

The researchers’ investigations suggest the impact threw more than 300 billion tonnes of sulphur into the atmosphere.

This would have dropped temperatures globally below freezing for several years.

Ocean temperatures could have been affected for centuries. The abrupt change explains why so many species struggled to survive.

“We always thought there was this global winter but with these new, tighter constraints, we can be much more sure about what happened,” Prof Joanna Morgan, from Imperial College London, told BBC News.

The new assessment is reported in the journal Geophysical Research Letters.

Lift boat MyrtleImage copyright    MAX ALEXANDER/B612/ASTEROID DAY
Image caption The drill project is revealing new insights on one of the most astonishing events in Earth history

The UK geophysicist was the co-lead investigator on the 2016 project to drill into what remains of the impactor’s crater under the Gulf of Mexico.

She and colleagues spent several weeks retrieving the rock samples that would allow them to reconstruct precisely how the Earth reacted to being punched by a high-velocity space object.

Their investigations suggest the asteroid approached the surface from the north-east, striking what was then a shallow sea at an oblique angle of 60 degrees.

Roughly 12km wide and moving at about 18km/s, the stony impactor instantly excavated and vaporised thousands of billions of tonnes of rock.

This material included a lot of sulphur-containing minerals such as gypsum and anhydrite, but also carbonates which yielded carbon dioxide.

The team’s calculations estimate the quantities ejected upwards at high speed into upper atmosphere included 325 gigatonnes of sulphur (give or take 130Gt) and perhaps 425Gt of carbon dioxide (plus or minus 160Gt).

The CO2 would eventually have a longer-term warming effect, but the release of so much sulphur, combined with soot and dust, would have had an immediate and very severe cooling effect.

Jo MorganImage copyright  MAX ALEXANDER/B612/ASTEROID DAY
Image caption   Prof Morgan pictured with some of the rock samples drilled from beneath the Gulf of Mexico

An independent group earlier this year used a global climate model to simulate what would happen if 100Gt of sulphur and 1,400Gt of carbon dioxide were ejected as a result of the impact.

This study, led by Dr Julia Brugger from the University of Potsdam, Germany, found global annual mean surface air temperatures would decrease by at least 26C, with three to 16 years spent at subzero conditions.

“Julia’s imputs in the earlier study were conservative on the sulphur. But we now have improved numbers,” explained Prof Morgan.

“We now know, for example, the direction and angle of impact, so we know which rocks were hit. And that allows us to calibrate the generation of gases much better. If Julia got that level of cooling on 100Gt of sulphur, it must have been much more severe given what we understand now.”

The generation of what has become known as the Chicxulub Crater was an astonishing event.

The initial hole punched in the Earth would have been about 30km deep and 80-100km across. Unstable, and under the pull of gravity, the sides of this depression would then have collapsed inwards.

At the same time, the centre of the bowl likely rebounded, briefly lifting rock higher than the Himalayas, before also falling down to cover the inward-rushing sides of the initial hole. And although this violent reconfiguration of the Earth’s crust took just minutes to complete, its consequences led to the fifth great mass extinction on our planet.


Chicxulub Crater – The impact that changed life on Earth

Drill siteImage copyrightNASA
Image captionThe outer rim (white arc) of the crater lies under the Yucatan Peninsula itself, but the inner peak ring is best accessed offshore
  • A 12km-wide object dug a hole in Earth’s crust 100km across and 30km deep
  • This bowl then collapsed, leaving a crater 200km across and a few km deep
  • The crater’s centre rebounded and collapsed again, producing an inner ring
  • Today, much of the crater is buried offshore, under 600m of sediments
  • On land, it is covered by limestone, but its rim is traced by an arc of sinkholes
CenoteImage copyright  MAX ALEXANDER/B612/ASTEROID DAY
Image caption    Mexico’s famous sinkholes (cenotes) have formed in weakened limestone overlying the crater

The project to drill into Chicxulub Crater was conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). The expedition was also supported by the International Continental Scientific Drilling Program (ICDP).