Butterfly pea tea, derived from the vibrant blue petals of the Clitoria ternatea plant, has captivated attention globally for its striking appearance. This unique beverage originates from Southeast Asia, where it has been cherished for centuries. Traditionally, the butterfly pea flower has been used as a refreshing drink and a natural dye in culinary applications. Its most intriguing characteristic is its ability to transform colors, making it a popular choice for beverages and food coloring.
The Pigment Responsible: Anthocyanins
The color-changing property of butterfly pea tea stems from compounds called anthocyanins. These natural, water-soluble pigments are responsible for the red, purple, and blue hues in many plants, fruits, and flowers. Butterfly pea flowers are particularly rich in a unique type of these pigments called ternatins. These ternatins contribute to the flower’s intense blue color when initially steeped.
How pH Influences Color
The scientific basis for the color change in butterfly pea tea lies in its interaction with pH levels. pH measures how acidic or alkaline a solution is, ranging from 0 (highly acidic) to 14 (highly alkaline), with 7 being neutral. Anthocyanin molecules undergo structural changes in response to varying pH levels. In a neutral to slightly alkaline pH environment, such as water, the anthocyanins reflect blue or purplish hues.
When an acidic substance is introduced, the pH drops. This shifts the perceived color as the altered structure absorbs and reflects light differently. As the solution becomes more acidic, the color transitions from blue to purple and eventually to pink or red. This reversible transformation showcases the anthocyanins acting as a natural pH indicator.
Achieving Different Colors and Safety
Understanding the influence of pH allows for intentional color manipulation of butterfly pea tea. Common acidic household items like lemon juice, lime juice, or vinegar can transform the tea. It shifts from its initial blue to a vibrant purple, and with more acid, to shades of pink or even red.
Beyond citrus, ingredients like hibiscus petals can create a fuchsia or bright red hue when combined with the blue tea. The color changes are a natural chemical reaction and are safe for consumption. Butterfly pea flower extract has been extensively tested, showing no adverse effects even at high doses. The anthocyanins are also found in many commonly consumed fruits and vegetables, reinforcing the tea’s safety as a natural colorant and beverage.