– 2 drops blue food coloring

Blue food coloring is a synthetic dye or natural colorant used to impart blue hues to food and beverages. Synthetic blue food colorings are primarily composed of FD&C Blue No. 1 (Brilliant Blue) or FD&C Blue No. 2 (Indigo Carmine), which are azo dyes certified for food use in many countries. These are water-soluble compounds derived from petroleum or coal tar sources, though some regions permit alternative synthetic or natural blue colorants such as spirulina extract or anthocyanins. The coloring is typically supplied in liquid, powder, or gel form, with liquid formulations being the most common in home cooking and professional kitchens.

Natural blue food colorings derive from sources such as butterfly pea flower (Clitoria ternatea), spirulina algae, or anthocyanin-rich fruits like blueberries, though these alternatives tend to have less intense color intensity and greater pH sensitivity than synthetic versions.

Blue food coloring is employed primarily in decorative and novelty applications rather than as a functional ingredient. It is commonly used in cake frostings, icings, glazes, and buttercreams to create visually distinctive desserts, particularly for themed celebrations such as baby showers, holiday gatherings, or character-themed cakes. The coloring also finds application in beverages including cocktails, smoothies, and decorative drinks, as well as in confectionery items such as fondant, macarons, and colored sugar. Small quantities—typically 1-3 drops of liquid coloring—are sufficient to achieve saturated blue hues without affecting flavor profile. Professional bakers often prefer gel-based colorings over liquid varieties due to their superior tinting strength and minimal effect on batter or frosting consistency.