Speaker 1: Welcome to brain Stuff from house Stuff Works dot com
Speaker 1: where smart happens. Hi Am Marshall Brain with today's question,
Speaker 1: what is mayonnaise? And this question comes up because lots
Speaker 1: of people have no idea what mayonnaise is. You know,
Speaker 1: if you look at butter, most people know that you
Speaker 1: can make butter out of cream. And if you look
Speaker 1: at catchup or something like that, most people know that
Speaker 1: it's made out of a thick tomato sauce. But mayonnaise,
Speaker 1: what what is it? Is it made out of milk
Speaker 1: because it's white? Is it some other substance? If you
Speaker 1: look at the label, you can see that it has
Speaker 1: a lot of fat in it. Some mayonnaises have as
Speaker 1: much as nine fat. So let's take a look at
Speaker 1: where this stuff comes from. It turns out that mayonnaise,
Speaker 1: and here we're talking about real mayonnaise, the kind of
Speaker 1: mayonnaise you could make at home if you wanted to,
Speaker 1: is made out of at least three things, and those
Speaker 1: are oil, a lot of oil, egg yolks, and some
Speaker 1: kind of acid, either lemon, juice or vinegar. There might
Speaker 1: also be some kind of seasonings in there, like salt,
Speaker 1: and maybe something else. But mayonnaise itself is just the
Speaker 1: three things oil, egg, yolks, and lemon juice or vinegar.
Speaker 1: The obvious question is, how are you going to get
Speaker 1: oil and lemon juice to mix together? Because lemon juice
Speaker 1: is water based and oil is oil based, obviously, so
Speaker 1: when you try to mix them together, they're not going
Speaker 1: to mix. Oil and water don't mix. And the magic
Speaker 1: of mayonnaise and mayonnaise really is kind of magic, is
Speaker 1: that the egg is there to act as an emulsifier
Speaker 1: and to make those two things that normally wouldn't combine
Speaker 1: able to combine together to create the unique taste of mayonnaise. Therefore,
Speaker 1: we say that mayonnaise is an emulsion, which is a
Speaker 1: mixture of any two liquids that normally can't be combined chemically.
Speaker 1: Mayonnaise is also known as a colloid. A colloid is
Speaker 1: a mixture composed of tiny particles that are suspended in
Speaker 1: another or immiscible or unmixable material. These particles are usually
Speaker 1: larger than molecules, but less than one one thousand of
Speaker 1: a millimeter in size. Small particles like this don't settle
Speaker 1: out or don't rise to the top, depending on their nature,
Speaker 1: and they will pass right through filter paper. One really
Speaker 1: good example of a colloid that we see all the
Speaker 1: time is homogenized milk. In homogenized milk, they've taken the
Speaker 1: cream and they've broken it up into such tiny particles
Speaker 1: that it remains mixed in with the watery milk. And
Speaker 1: it's the size of the particles that allows that to happen.
Speaker 1: So that's a mechanical colloid, a colloid that was created
Speaker 1: mechanically by breaking those cream particles up into such small,
Speaker 1: tiny spheres. Chemically, you can also create an emulsion, so
Speaker 1: you use chemicals of some sort to break the particles
Speaker 1: up and get them to suspend in a liquid. So
Speaker 1: to make mayonnaise, you start with the lemon juice and
Speaker 1: to that you add some egg yolk eggs, which contain
Speaker 1: an emulsifier called less than bind the ingredients together and
Speaker 1: prevent them from separating. So you add the eggs and
Speaker 1: the lemon juice, and those are going to combine together fine.
Speaker 1: Then you add the oil in a tiny bit, like
Speaker 1: just a few drops at a time, and whisk that
Speaker 1: together with a fork or with an actual metal whisk
Speaker 1: to get the oil and water emulsion started. If the
Speaker 1: chef messes up with this initial mixing step, the whole
Speaker 1: batch isn't gonna work. You have to start very slowly
Speaker 1: with the oil and get the emulsion to start, and
Speaker 1: then you can add more and more oil more quickly
Speaker 1: because the process accelerates as the mayonnaise thickens. Then, if
Speaker 1: you want to add in any seasonings to make flavored mayonnaise,
Speaker 1: you add them in at the end of the process.
Speaker 1: Since homemade mayonnaise isn't cooked, you need to be sure
Speaker 1: to use the freshest eggs possible, and you need to
Speaker 1: be pretty sure that they're free from salmonella. You also
Speaker 1: want to use it quickly. You can store it in
Speaker 1: the refrigerator for two or three days, but after that
Speaker 1: you really should throw it out rather than letting it
Speaker 1: hang out for a week or two. Commercial mayonnaise, which
Speaker 1: is the kind of mayonnaise you buy at the store
Speaker 1: in a jar, will last up to six months in
Speaker 1: the refrigerator. It contains by US law at least oil
Speaker 1: by weight, except for reduced fat and fat free mayonnaises.
Speaker 1: The standard of Identity law also requires that all commercial
Speaker 1: real mayonnaise use only egg as the emulsifier. Reduced fat mayonnaise,
Speaker 1: which isn't considered real mayonnaise anymore, usually contains modified food starts,
Speaker 1: cellulose gel, and other thickeners and emulsifiers. Once you have
Speaker 1: your mayonnaise, you can use it straight up on something
Speaker 1: like a bacon lettuce tomato sandwich, or you can use
Speaker 1: it as a base for other sauces like tartar sauce
Speaker 1: or a Thousand Islands salad dressing. Be sure to check
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