Collins, who opened his business in the city’s Trinity Market 12 years ago, said: “The optimum temperature for making chocolate is 18C.
“When it reaches 30C, the fat – the cocoa butter, in our case – starts to melt.
“Due to the current temperatures, we have have temporarily stopped production.”
While Hull is not included in the severe weather warnings issued by the Met Office, temperatures in the city are expected to exceed 30C by the end of the week.
While he may be missing out on chocolate sales, Collins said chocolate milkshakes were proving the perfect thirst-quencher.
“We’re making iced milkshakes using the molten chocolate,” he said. “And they’re flying out.”
Chocolates made before the heatwave should fare well, however.
“It’s all down to the fat that is used,” he added. “A lot of the mass-produced chocolate contains more fat and it’s often palm oil, whereas artisan makers like us tend to use cocoa butter.
“That’s why when the temperatures reach 18C plus, you’ll often find chocolate bars looking a bit mushy in the supermarkets.”