At the confluence of food safety and marketing, blue raspberry was born.
In the natural world, no raspberry looks or tastes anywhere close to “blue raspberry.” The “raspberry” flavor of blue raspberry was created as a combination of banana, cherry, and pineapple. As for its shade of electric blue, most raspberries are red but there are some blue-ish raspberries. The white bark raspberry, native to western North America, is a very dark (nearly black) shade of blue. So why do we have the flavor and color of blue raspberry?
Red Number 2
In the 1950s there was a growing movement in the U.S. to ensure the safety of food and food additives. People had increasing doubts over the safety of Red No 2 (a food dye that, at the time, was made from coal tar). Food companies could capitalize off of this concern if another color was used.
It was during this time that the Gold Medal company of Cincinnati introduced a new flavor of blue raspberry cotton candy. Its popularity took off when Icee introduced their blue raspberry flavored frozen drink in the early 1970s. The competition between blue raspberry and red flavored candies/drinks was taken to a new level in 1976 when Red No 2 was banned in the United States because it was potentially carcinogenic. Simply put, at the time, Blue No 1 was safer than Red No 2.
Marketing
To mimic real life, food companies then and now use the color red for lots of flavors: cherry, apple, cinnamon, watermelon, cranberry, etc. It’s a crowded space. However, there are not many foods that are naturally blue, which as a marketing opportunity was very attractive. Blue was a way to set raspberry apart from the other flavors. This is similar to why pink lemonade exists: lemonade isn’t pink, but pink is a bright color that stands out from the crowd. Blue raspberry had the color all to itself for a long time which was marketing gold.