Here’s an “aha!” moment or an interesting little scientific fact to trot out at the next braai or social occasion. Want to know why people love sour flavours? It’s because it engages the brain’s reward system – specifically activating dopamine, a neurotransmitter associated with feeling good.

An article by Katherine Wu in The Atlantic stated that the human body’s senses have been well studied. Researchers know that sweetness is craved for calories – and thus the preservation of life. The desire for the fifth sense, umami or savouriness keeps humans and animals supplied in protein. Salt is vital to stay hydrated and keep the body’s fluids in balance and bitterness is a warning sign that something might be toxic.

Research has shown that even animals still have sour receptors and scientists theorise that this is so that they know if food has spoiled or wheter it’s safe to eat. Cats, for example, can taste sour – but not sweet.

Sourness is not needed for nutrition or to alert humans to potential danger. It’s simply a sign of low pH or the presence of acidity. It’s the latter factor which researchers think why that sense hasn’t been evolved out of existence. Sourness can point to food being high in vitamin C – as Wu wrote; “a nutrient that our ancestors lost the ability to manufacture about 60 to 70 million years back. A fresh appetite for sour might have helped spare us the ravages of scurvy.”

The whisky sour cocktail officially dates back to the 1860s – but because of scurvy and its impact on seafarers, the British Navy’s sailors had been consuming something similar to the sour well in advance of that.

Cocktail historians owe New York bartender Jerry Thomas a massive debt of gratitude since he penned the book that everyone refers to. In 1862 he published the first ever cocktail recipe book titled The Bar-Tender's Guide. It consisted of a variety of mixed drink recipes, including 10 cocktail recipes that would ultimately become the blueprint for future cocktail manuals.

Before Prohibition began in 1920, America enjoyed what’s known as the golden age of cocktails.

As Tim Nusog wrote on Liquor.com, spirit, citrus and sugar are considered the trinity of the classic sour – the oldest types of cocktails. And the whisky sour has been around for at least 150 years. Its precise origin can’t be pinpointed but it was already widely enjoyed when Thomas penned his famous book.

The whisky sour is a drink customarily made with two parts whisky (or American bourbon), to one of lemon juice, a half part each of simple syrup and egg white for the trademark frothy top after all the ingredients are shaken together and served over ice, garnished with a maraschino cherry or an orange slice.

There are some similarities between bourbon and Irish whiskey but the American spirit’s trademark caramel sweetness and nutty nuance is far more obvious and ‘in-your-face’ than whiskey from the emerald isle. The result is a sour cocktail in which the lemon zip and tang is more pronounced.

The Big Beast Sour is one of a host of variants in which the spirit base of the cocktail is altered. In this case, a heavily peated, smoky Islay malt is used for maximum effect.