Does cream change on a molecular level when it’s turned into butter?

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Heavy cream doesn’t melt when heated, it actually thickens. But if you turn heavy cream into butter, the whey separates from it and you’re left with a solid that’s mostly fat, but then if you heat that solid, it turns into a liquid that is THINNER than heavy cream.

I don’t understand how that’s possible.

In: Chemistry

2 Answers

Anonymous 0 Comments

Cream is an emulsion of fat in aqueous (watery) stuff. The aqueous stuff is whey, and yeah if you get rid of it all you are left with the milk fat which is a solid at room temperature.

Milk fat is a liquid at cooking temperatures. The reason it has lower viscosity than the cream is (1) I don’t think it actually does have lower viscosity, but (2) even if it does viscosity of emulsions is complicated, and yeah they can sometimes have a high viscosity.

The cream “thickening” is from you evaporating off the water which leaves more fat in the emulsion. Eventually it’ll “break” and the fat will separate on a top layer.

Anonymous 0 Comments

In some ways, it depends on what you mean by “on a molecular level”.

Do the ways the molecules interact with each other change? Yes, the whey no longer being a part of the fat will cause the butter to act more like a fat and less like a liquid.

Do the molecules drastically change form? Not really. It’s still fat molecules and whey molecules, they just aren’t as mixed together anymore.

You can think of it as something similar to two people standing in a room. When they are both in the room, they can talk to each other or do whatever 2 people can do. But if they are put in different rooms, those interactions are no longer available, they are no longer a group. The people are still the same, but the environment has changed.