You’ve just taken a devil’s food cake out of the oven and set it on the counter to cool. Moment by moment, your house fills with the unmistakable, diet-crushing aroma of chocolate, and your mouth fills with watery saliva.
As chemist Hadi Fares explains in the video above, saliva has a number of functions, but the one that’s relevant here is that it helps us eat. Saliva lubricates the food we’re eating, helping us work it around in our mouths for chewing and tasting. It also contains enzymes that start the digestion process before you even swallow.
The phrase “mouth-watering” is actually pretty accurate. There are two types of saliva: mucous and serous. Mucous saliva is exactly what it sounds like—thick, sticky, and full of mucus. Serous saliva, on the other hand, is nearly all water, and that’s what floods into your mouth at the smell, sight, or thought of especially delicious food.
Making saliva is your body’s way of yelling excitedly about the food in front of you. WE ARE GOING TO EAT! says your brain. YES! WE ARE GOING TO EAT CAKE! agree your salivary glands, eagerly pumping spit into your mouth.
What happens next is up to you.