(ethereal electronic music) - [Narrator] Valentine's Day is here, and whether you're spending it with your significant other or drowning in the misery of your total loneliness, (air whooshing) chocolate is often in the mix, but if you're gonna go overboard on chocolate this year, what's the best choice?

(air whooshing) In this corner, mixed in at under 20% cacao, we've got creamy milk chocolate, and in the other, weighing in at over 45% cacao, you've got complex and alluring dark chocolate.

It's time to settle this dispute in the Chemistry Thunderdome.

(crowd roaring) Who will come out on top of this scientific face-off?

(energetic music) (crowd roaring) (bell clanging) (crowd roaring) It's long been believed that chocolate is a free ticket to Friskyville, and if it's true, the real question is what chemicals in chocolate can trigger the romance?

Given the higher concentration of cacao in dark chocolate, we can unscientifically guess that the darker the chocolate, the sweeter the emotion.

Also note that we're using the word cacao, as that's the term chocolate-makers use for the sum of all ingredients from a cocoa plant.

Your brain produces a chemical called phenylethylamine, or PEA, which helps release dopamine and norepinephrine, which are big-time players in feeling loved, and you guessed it, phenylethylamine can be found in trace amounts in chocolate.

Problem is, folks, when it hits your gut, your body quickly begins to metabolize it, leaving no legitimate effect on your brain.

In the end, when it comes to chocolate, it might just be that old-fashioned placebo effect, which means that the aphrodisiac round ends in a draw.

(bell clanging) (crowd roaring) You may have heard that chocolate has some great health benefits.

This is due to an abundance of potentially healthful plant compounds called polyphenols and in particular, a group known as flavanols.

In the laboratory, these compounds have been shown to have antioxidant effects that may result in combating cancer-causing free radicals, lower blood pressure, and limit the progression of heart disease.

(chime tinkling) Due to higher concentrations of cacao in dark chocolate, it packs a higher quantity of polyphenols than its milk counterpart, but that's not all.

Flavanols have been shown to up the release of nitric oxide, which opens your blood vessels and may lead to better heart health.

Also, eating dark chocolate can deliver equal or greater amounts of antioxidants as red wine, berries, and green tea.

Let's be real, folks: chocolate's no health food, and more research is needed on antioxidants' potential health benefits, but higher flavanol content gives dark chocolate a small but slight edge, giving it the win.

(bell clanging) (crowd roaring) Texture, or mouthfeel for the foodies, is one of the most incredible characteristics of chocolate and in particular, how it melts into a velvety smooth goo that coats every surface of your mouth, giving you nothing but unfettered flavor.

All chocolate bars are composed of a mix of this stuff, but milk chocolate also has condensed or powdered milk, and when it comes to smooth texture, those milk products are what really knocks its smoothness out the ballpark.

Milk proteins can add an incredible melty creaminess to a bar of chocolate.

Casein proteins from milk act as an emulsifier and help keep other ingredients mixed together.

The milk's butter fat softens the cocoa butter, making for a smooth, even melt, rather than the fats and roasted plant bits losing touch and getting all clumpy.

Even though dark chocolate has a nice texture of its own, milk chocolate is gonna have to take the win this round.

(bell clanging) (crowd roaring) Pretty much everyone knows what chocolate tastes like, but its complexity can be hard to pin down with words.

The real flavor of chocolate comes from cocoa beans, whose flavor profiles are drastically enhanced by the process of both fermentation, like when you make bread, cheese, or beer, and roasting, as in delicious coffee.

In cocoa beans, compounds called methylxanthines, which include caffeine and theobromine, contribute to a chocolate's bitterness and a little buzz for you.

Those polyphenols we talked about contribute to that bitterness too.

They also give a sort of earthy green note that's very particular to chocolate.

Amino acids and peptides in cocoa beans, along with the bean sugars and carbohydrates also mean the Maillard reaction explodes during roasting, giving chocolate its characteristic bold flavor.

Volatile compounds play a big role in defining the characteristic choco flavor as well.

Researchers have identified over 700 different compounds in chocolate vapors, but here's where it gets tricky: with the incredible biodiversity of cocoa plants, each strain exhibits its own flavor profile.

With dark chocolate, you find more strains, meaning that there are gonna be more complex flavors, giving it a win for the flavor round.

(crowd roaring) (bell clanging) Milk chocolate tends to be a lot easier on the pocketbook, and the reason is simple: the more cocoa, the more expensive.

If you're a candy maker and don't use as much of your expensive product, you can make a lot more servings and recoup your costs with higher margins, so when it comes to economics, folks, milk chocolate takes the win.

(crowd roaring)