A jump in the price of an onion can trigger more frustration than an expensive bottle of wine. The reason is simple: onions are part of everyday life.
They are bought regularly, used in familiar meals, and their price is easy to remember. When that price rises, consumers do not just see a more expensive vegetable. They feel the squeeze on their household budget.
A 21% surge in South African onion prices, pushing average 10kg bags to almost R100, has left shoppers feeling the pinch at the till.
But the outrage over a humble kitchen staple isn't just about supply and demand; it’s rooted in behavioural economics. When the price of an everyday necessity jumps, it triggers a psychological sense of financial loss that hits consumers far harder than a luxury splurge.
Why everyday prices hit harder
Behavioural economist and University of Cape Town professor Martine Visser said consumers are more likely to notice price increases on products they buy regularly.
“The reason why people get upset with the price of something like an onion rise is that it is a necessity or staple food,” Visser said. “Most people consume it weekly whether they are wealthy or poor.”
Because consumers encounter these prices repeatedly, increases remain visible.
“A price increase signals a loss to the consumer, something most people are averse to,” she said. “And this feeling of loss will probably be triggered several times in the days and weeks after the price increase occurs.”
That repeated exposure can make a small increase feel significant over time.
The feeling of getting poorer
Staple food prices can also become a measure of household financial health.
Visser said consumers may associate rising prices of everyday foods with inflation and their purchasing power.
“So, people feel poorer when prices of such goods increase, especially if their incomes have not been adjusted accordingly,” she said.
This helps explain why a higher onion price can provoke more irritation than an expensive luxury purchase. A luxury item is usually bought less often and may be seen as a discretionary expense. An onion is something consumers expect to buy regardless of their income.
When shopping becomes a mental calculation
Rising food prices can also change how people shop and cook.
“People may switch to substitute foods, seek other shops that sell the product for cheaper, make do without it in their favourite recipe or start stockpiling when they find a cheaper source,” Visser said.
Those decisions can create another psychological burden because consumers are constantly reminded that they must adjust.
“All these forms of effort remind them of what they have lost and are likely to cause some form of ongoing unhappiness or dissatisfaction,” she said.
The onion spike may not last
The latest increase could ease as supply improves. Food For Mzansi and the Agricultural Market Trends database indicate that warmer temperatures over the coming weeks are expected to increase production and bring more onions to market.
Demand is also expected to soften by late August, which could ease pressure on prices.
That offers some relief for consumers, particularly as South Africa's broader food inflation picture remains relatively subdued.
Agricultural economist Wandile Sihlobo said consumer food price inflation slowed to 0.6% in July 2026 from 1.4% in June, its lowest level since 2010. He attributed the decline largely to strong agricultural production, with grains, fruits and vegetables remaining in deflation.
Yet consumers may still react strongly to individual price increases.
“People in general tend to remember the prices and price changes of products they use often more than the ones they buy occasionally,” Sihlobo said.
“Thus, there tends to be more reaction to changes in food product prices, as with onions in this case.”
lutho.pasiya@nationalmg.co.za