Hi I'm Elliott and this is Mental Floss and today we are here at the YouTube Space, LA. Today I'm gonna answer Tony's Big Question: why do certain things taste so bad after having brushed your teeth?

So, people tend to notice this when they brush their teeth and then drink orange juice, and the result is, uh, unpleasant. In fact, according to a 2005 study published in the Journal of Sensory Studies toothpaste will have an impact on the taste of orange juice for at least an hour after brushing one's teeth.

And today I'm going to tell you why that is with the help of two friends: Dr. Bunsen Honeydew and his assistant, Beaker. Let's get started.

[Mental Floss intro plays]

Honeydew: Hello there science fans. Beaker and I are eager to discuss this topic.

Beaker: (signature Beaker mumble)

Honeydew: Yes, we brush regularly, you see, even though technically we don't have teeth.

Elliott: It's actually an agent in the toothpaste that makes various foods and drinks taste awful after you brush. Isn't that right, Bunsen?

Honeydew: That's right! Most toothpastes contain either sodium laureth sulfate or sodium lauryl sulfate. Ooh, isn't that fun to say, Beakie?

Beaker: (signature Beaker mumble)

Elliott: Like soap, these are surfactants, meaning they lower surface tension and are responsible for the foamy-ness of toothpaste.

Beaker: (signature Beaker mumble)

Elliott: Anyway, sodium lauryl sulfate and sodium laureth sulfate actually affect taste buds. They decrease our capacity to taste sweeter flavors by suppressing the taste bud receptors that detect those types of flavors. They also break down phospholipids -

Honeydew: Phospholipids!

Elliot: - on the tongue which makes bitter tastes more detectable.

Honeydew: Demonstrate, Beaker.

Beaker: (signature Beaker mumble) (coughing and making noises)

Elliott: So that was an orange rather than orange juice, but you get the point. This is done in a way similar to how dish detergent can break down oils on dishes. Fatty membranes -

Honeydew: Fatty!

Elliott: - that surround the cells in our mouths get temporarily disturbed by the surfactants, so whatever you eat or drink after brushing will, you know, taste more bitter and less sweet than usual.

[Mental Floss music starts to play]

Elliott: Thank you for watching Mental Floss on YouTube which was made with the help of all of these nice people and thank you to Bunsen and Beaker for helping me out today. If you have a 'big question' of your own that you would like answered, leave it in the comments below and we'll see you next week.

Honeydew: I have a big question.

Elliott: Yeah.

Honeydew: Do you have anything for male pattern baldness?

Elliott: Ooh, uh not on me, actually.

Honeydew: Hm.

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