Seltzer water can contribute to making a cake fluffier by introducing carbon dioxide (CO2) bubbles into the batter. The CO2 bubbles from the seltzer create air pockets, which expand during baking and help the cake rise, resulting in a lighter and fluffier texture. This effect is similar to what happens when you use baking powder or baking soda in a cake recipe, as they also release carbon dioxide when mixed with liquid or exposed to heat.
When seltzer water is incorporated into the cake batter, the carbon dioxide bubbles expand due to the heat in the oven, causing the cake to rise. This process helps create a more open and airy crumb structure, making the cake lighter and fluffier compared to using plain water or other liquids without carbonation.
It's important to note that using seltzer water alone is not the only factor that determines the fluffiness of a cake. The recipe's overall composition, including the type and ratio of ingredients, mixing technique, and baking conditions, also play significant roles in achieving a light and fluffy cake. Additionally, seltzer water can impart a slightly different taste to the cake compared to using plain water, as it contains dissolved minerals and may have a faintly tangy or effervescent flavor.
If you're interested in trying seltzer water in your cake recipe, consider using it as a substitute for regular water or other liquid ingredients. Keep in mind that the impact on the cake's fluffiness may vary depending on the specific recipe and other factors, so experimentation and adjustments might be needed to achieve the desired result.