Fun Friday – Making butter!

Last week the Fun Friday blog was all about density, how less dense liquids will sit on top of more dense liquids and how some liquids such as oil and water do not mix!

Milk and cream are quite like the oil and water mix as they are made up of fat and water.  So why do they not separate into two layers like the oil and water we used last week?  That is because the fat is broken up into tiny little droplets that float evenly throughout the water.  This is an example of an emulsion.  

For today’s Fun Friday we separated the fat from the water in cream and made some yummy butter!  My Fun Friday Science Team really enjoyed this experiment especially as they got to eat the results… spread thick on their favourite bread!

How to make butter…

What you will need: double cream, salt (optional) a jar with a screw tight lid (preferable plastic!) and a
marble (optional)

Add the marble (if using) and the cream to the jar (no more than half full).

Add salt (if using) … we used about half a teaspoon.

Put the lid on tight and start shaking….

….And shaking….

…And shaking!

First it turned to whipped cream, then small lumps of butter started to form!

Keep shaking (about 10-15 minutes) until the butter lumps start to get bigger and clump together
and you can see the watery bit separate out.

At this stage you can stop shaking (phew!); now you want to separate the butter from the watery bit
(which is actually buttermilk!).

We used clean muslin to separate the butter from the buttermilk, but a few sheets of
kitchen roll will work too, or even a clean tea towel.

Squeeze the lump of butter to remove more of the liquid!

Et voila!  You end up with a lovely yellowy lump of butter and some buttermilk
(we used our buttermilk for making bread!)

You can add salt at this stage instead if you prefer!

We made this! 

So what happened (the science bit!)?…

As I mentioned the cream is an emulsion…. a liquid suspension of tiny droplets of one liquid floating in another liquid.  In this case tiny droplets of milk fats float in mainly water.  When we shake the mixture the tiny droplets of fat collide with each other and the fat sticks together.  If we keep mixing most or all of the fat will stick together in one big lump, completely separated from the water.  The resulting lump of milk fats is our butter!
This was a really fun and simple experiment that made my kids think about the science behind their food and where it comes from.  It has started a number of discussions in our home and no doubt will lead to a few more posts on this blog!  Of course once we had made the butter I had to make some yummy bread to put it on and now the kids want me to make the blackberry jam from our stash in the freezer.  🙂
Enjoy your weekend!
If you try out this experiment or have any questions or things to add, do please leave a comment below, we love to hear from you!


Science blogger and writer; Owner of Dr. How's Science Wows; Mother of three junior scientists who have taught me that to be a great scientist you need to look at life through the eyes of a child!

4 thoughts on “Fun Friday – Making butter!

  • September 16, 2013 at 11:10 am

    I tried making it once with our own milk – tried skimming off the cream but it wasn’t successful – I think I rushed the skimming part. Will try it again when I have time 🙂
    That’s a lot of shaking – well done

    • September 16, 2013 at 11:51 am

      Was wondering if you had ever tried with your own milk… we used double cream here which made it extra easy… lots of shaking but not as much as I had expected and no one lost interest which was great :0) Good luck if you do try again, nice sense of achievement, kids loved using their own butter!

  • September 15, 2013 at 3:12 pm

    Fantastic post… excellently explained!
    I wish you were around when my boy was younger. Although, it might still interest him now….I must give it a try.

    You have quite an adorable Fun Friday Science Team 🙂

    xx Jazzy

    • September 15, 2013 at 7:00 pm

      Thanks so much…. yes they are lovely helpers although you would be amazed what can go wrong with this crew “helping”; Your son might prefer the teabag rocket experiment my teen nephew loves it! x

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