Why You Can't Use Basic Food Dye To Make Colorful Ice Cubes

Colored ice cubes are a fun addition to kids' drinks, or they can elevate a cocktail to a whole new level (even if you rely on at home cocktail hacks to prop up your mixology). Unfortunately, they're not as simple to make as you might think. In fact, several Reddit users have complained that their attempts colored cubes came out looking more like lost deep-sea creatures. Specifically, the food coloring was gathered in the center of the ice cubes, while the ice around this core was riddled with bubbles.

Several factors are working together to create the odd phenomenon. A Redditer suggests that the culprit may be propylene glycol, a food-safe anti-freeze, stabilizer, and emulsifier which is often found in food coloring. Propylene glycol can prevent food coloring from freezing, or increase the time it takes to do so.

In addition to the coloring potentially failing to freeze, water never freezes uniformly. Instead, the edges, bottom, and top of an ice cube freeze before the middle. You will have noticed this if you've ever taken an ice cube tray out a little too early and found a tough crust and a sloshy middle. Interestingly, this outside-in freezing process pushes impurities towards the center. This is why freezer ice is sometimes cloudy, with minerals and air bubbles at its center. No matter how well mixed in it is, food coloring is an impurity and will be pushed to the middle of your ice cubes as part of the freezing process.

Food coloring isn't the only way to make colored ice cubes. Other options include fruit-infused water, herbal teas you can make at home, or even using edible flowers to give your water vibrant, natural colors.

There are hundreds of options for making fun, bright rainbow ice cubes, so we can't list them all. Some of the best are practically flavorless, including saffron for a rich yellow, blue spirulina for a blue-green color, or butterfly pea flower for a wonderful, vibrant purple. These ingredients just need to be steeped in hot water until the color you need is achieved. Once you've let your the rainbow water cool, pour it into ice cube trays and freeze.

No matter what colorant you use, removing impurities such as minerals from your water will give you clearer ice and brighter colors. Filtering is the best way to do this, although results may vary depending on the at-home water filter you use. If you don't have a filter, don't worry. Tap water is totally fine for making ice, but you may end up with some cloudy centers if you live in a hard water area.

Other natural ingredients that create vibrant colors perfect for party ice cubes also add flavor to the water they're steeped in. This can be a good thing, offering an opportunity to design cocktails and mocktails that get more interesting as they're being sipped, changing both flavor and color. Favorites include hibiscus tea, also known as agua de Jamaica, chamomile, and frozen fruit juices.

Hibiscus imbues a deep reddish purple color. It has a tart but subtle flavor often likened to cranberry or pomegranate when sweetened. As it melts, it could turn lemonade into jamaica lemonade, or adding depth to a cocktail. Jamaica ice cubes would work great in a kombucha cocktail, for example, or, as agua de Jamaica is a very popular drink in Mexico, it might add a little something to mezcal drinks.

Chamomile tea should freeze into gentle, golden ice cubes, and add floral nutty notes that work with honey and citrus, while frozen fruit juices or blended frozen fruit offer pretty much endless flavor and color options. Finally, edible flower ice cubes are another way jazz up your drinks this Summer (or Autumn, or Winter, or Spring). Flowers or petals can even be frozen into colored ice for an exciting mid-drink reveal! 

With so many options for making ice cubes part of the fun, who cares that food dye doesn't work? Natural rainbows, floating flowers, and flavor-changing beverages are bound to wow your guests (or your kids).