Can growing conditons affect the flavour of your food?
We know good soil makes for healthier plants, but can soil produce better-tasting fruits and vegetables? Many in the food industry insist that soil composition is the key that makes foods taste a particular way.
The term "terroir" is often used by chefs, TV shows and cookbook authors to describe how the growing conditions of a specific region impart flavour to the food grown there.
It leads to the idea that those tomatoes grown on Italian mountainsides are somehow special. The weather on that slope, the geography and, above all, the composition of the soil make those tomatoes taste a particular way.
That's why shoppers willingly pay more money for particular wines, coffees, chocolates and endless varieties of fruits and vegetables.
But before you slap down a premium for San Marzano tomatoes, grown in the volcanic soil of Italian hillsides, here's what science says about the romantic notions of terroir.
John Reganold, a leading soil scientist at Washington State University, says while soil conditions can make food taste better, the effect of soil is hard to isolate from, say, the effects of light or water.
"It wouldn't be in the scientific literature because it is very hard to measure the impact of terroir on taste," he explained.
Despite the difficulty in studying soil's impact on taste, Reganold set out to do just that. He found 26 strawberry farms in California where he tested 31 traditional soil properties like organic matter and microbial activity.
Apart from the soil, other aspects of terroir like climate and geography were the same. It turns out higher-quality soil does indeed produce more nutritious berries that are more shelf-stable.
But when it comes to taste, the results from a panel of tasters were inconclusive. They liked strawberries from a whole range of farms with a whole range of soils. And while that doesn't mean terroir isn't real, it just means taste is awfully subjective.
"It certainly affects yield," Reganold said. "Does it affect taste if you weren't to, say, add as much organic matter as you're adding? Probably. Is that easy to measure? No."
In other words, eating a strawberry in a sterile lab, under scientific scrutiny, may itself make us perceive flavour in different ways. Conversely, who hasn't tasted a perfect berry in a sun-dappled field and decided it's the best thing they've ever tasted?
Subjectivity isn't good for science. And that's why, even though we know the effect is likely very real, it's hard to definitively measure how soil changes the way food tastes.