Recap
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Latte art has a 26-year history, but references to milk mixed with coffee go back more than 300 years.
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Milk is approximately 87% water.
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The other 13% is mostly made up of sugar (lactose), fat, and protein.
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Casein protein helps as an emulsifier.
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Whey protein helps stabilise milk foam.
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When entraining air, it’s helpful to add the air before the milk gets hot and to increase the volume of the milk by 33%.
New Words
Emulsifier A surface-active substance that helps stabilise an emulsion.
Entraining The process of injecting air into the body of a current of liquid in a way that holds it in suspension
Latent heat Energy that is absorbed or released by a substance as it changes phase (e.g., from a gas into a liquid)
Macrobubbles A foam made of large bubbles; in a latte foam context, bubbles greater than 0.5 mm in diameter are undesirably large.
Microfoam A foam comprised of very small, uniform-size bubbles having a diameter usually less than 500 um
Surfactant A ‘surface active agent’ which lowers the surface tension between substances; surfactants are integral to the performance of detergents, wetting agents, emulsifiers, foaming agents, and dispersants.
End 0.5