How To Cool Down Your Mouth From Spicy Food, According to Science

Chileheads have long debated the best way to cool your mouth down after eating spicy food. It has become widely understood that water is not the best way to go, as it may help in the moment but ends up just spreading the spicy around. Milk tends to be the prefered solution, and people often argue this is because of the fat content of milk. Well, according to new research, this is only part of the story. While higher fat content does seem to help, the protein content in milk is also doing a lot of the work providing relief from the heat. 

In a study by Justin Gaiser and John E. Hayes for the Sensory Evaluation Center at Pennsylvania State University, a number of different milk types were put to the test:

As expected, full fat cow's milk was the most effective milk for heat relief. But interestingly, ultra-filtered whole milk did even better. Ultra filtered milk has the same fat content as regular milk, but is higher in protien content because much of the sugar has been filtered out. 

 In a second study, they narrowed in on soy milk in particular, finding that higher protein content predicted better burn relief. 

Why does protein have such a large impact? According to the American Chemical Society, it likely has to do with polarity. Capsaicin, the chemical that makes chiles spicy, is nonpolar, and so it can only be disolved with other nonpolar substances. Casein, a key milk protien, is one such substance, so "casein molecules attract capsaicin molecules. They surround the capsaicin molecules and wash them away, in the same way that soap washes away grease." They go on to mention that cottage cheese is primarily casein, so if you can't find ultra-filtered milk, that may be another promising way of cooling your mouth down after eating spicy food.

Source for images here.