# cream vs. butter questions

**URL:** <https://boards.straightdope.com/t/cream-vs-butter-questions/839439>\
**Category:** Cafe Society\
**Created:** [August 29, 2019, 9:32pm UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439 "2019-08-29T21:32:04Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\
**Post date:** [August 29, 2019, 9:32pm UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439/1 "2019-08-29T21:32:04Z")

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Why does raw milk separate into skim milk and cream rather than skim milk and butter? Why is a second step necessary to churn out butter? And what difference if any is there between skim milk and the buttermilk\* left over from butter churning?

\*The original definition of “traditional” buttermilk, the liquid leftover from making butter. Modern “cultured” buttermilk is basically fermented milk.

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**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\
**Post date:** [August 29, 2019, 10:34pm UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439/2 "2019-08-29T22:34:32Z")

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[Wikipedia says](https://en.wikipedia.org/wiki/Butter)

> [@Wikipedia](#):
>
> Unhomogenized milk and cream contain butterfat in microscopic globules. These globules are surrounded by membranes made of phospholipids (fatty acid emulsifiers) and proteins, which prevent the fat in milk from pooling together into a single mass. Butter is produced by agitating cream, which damages these membranes and allows the milk fats to conjoin, separating from the other parts of the cream.

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**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\
**Post date:** [August 29, 2019, 10:57pm UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439/3 "2019-08-29T22:57:41Z")

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Thanks **markn+**. Does that make the liquid portion of cream just what amount of skim milk the globules “drag” with them when cream separates?

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**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\
**Post date:** [August 30, 2019, 11:27am UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439/4 "2019-08-30T11:27:45Z")

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> [@Lumpy](#):
>
> Thanks **markn+**. Does that make the liquid portion of cream just what amount of skim milk the globules “drag” with them when cream separates?

Think of it more as whatever fills the spaces around the cream globules - like if you had a pile of marbles, all the air spaces would be that liquid.

And the buttermilk left over from butter churning is essentially _fermented_ skim milk.

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**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\
**Post date:** [August 30, 2019, 12:03pm UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439/5 "2019-08-30T12:03:22Z")

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Apparently, during the time when cream separates from the rest of the milk, it begins to ferment, and traditional butter making allows that to continue in the collected cream because it makes butter easier to churn.

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<div class="post-metadata">

**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\
**Post date:** [August 30, 2019, 12:07pm UTC](https://boards.straightdope.com/t/cream-vs-butter-questions/839439/6 "2019-08-30T12:07:29Z")

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> [@MrDibble](#):
>
> Think of it more as whatever fills the spaces around the cream globules - like if you had a pile of marbles, all the air spaces would be that liquid.
> 
> And the buttermilk left over from butter churning is essentially _fermented_ skim milk.

Yes and no. Before refrigeration and mechanical separation, by the time cream rose it had already started to ferment, or “culture”. On the other hand if you start with modern fresh cream it won’t have fermented yet. Modern cultured buttermilk is an imitation of traditional buttermilk by fermenting skim milk.