View Full Version : How do i know how much to substitute?

02-01-2010, 09:12 PM
hi all,
im new here & really keen to start making soap, saw it on kirsties homemade home program and am hooked!
im going to follow her recipe that she did as it looks easy and its my first time, what i would like to know is,if i want to use different butters/oils how do i know how much to change from the original recipe?
hers uses coconut oil,sunflower oil & olive oil.

was thinking of maybe adding shea butter or coco butter.
hope this makes sense!

02-01-2010, 09:23 PM
(welcome) to the forum

We shall be posting our soap making course dates next week.

Learn about recipes and superfatting your soaps.


02-01-2010, 09:26 PM
(welcome)nice to see you here.

02-01-2010, 09:38 PM
Doodlebug, please, please be careful about substituting anything into an existing recipe. A friend of mine got it wrong and put too mcuh essential oil into her soap and it brought her out in a rash. If you are planning on selling it, you soap must be tested - I'm not sure I would let my family loose on a bar of untested soap.

If you're going to use essential oils in your soap - use Lavender - it's relatively safe on the skin.

Good luck
Love Poppy xxx

02-01-2010, 10:04 PM
thanks for the replys.
im not going to be selling , just going to be doing it as a hobby.
i was realy interested in how to add an extra oil/butter so i could have maybe a more moisturising/luxurious bar of soap - maybe i need to trawl internet for better recipies?!

must admit im starting to confuse myself now,im a bit like a kid in a sweet shop -got xmas money to spend & there is WAY too much temptation of lovely thing on websites!
i realy want to do a rose or turkish delight scented bar with pretty bits in it!

03-01-2010, 09:43 AM
Hi Doodlebug

Each oil needs a different amount of caustic soda (lye) to turn it into soap, if you add too much you will make a soap that will too alkaline and sting you and if you don't add enough then the soap will be very soft.

Soap makers use something called a saponification chart or calculator to work out how much caustic soda is needed for the amounts of oil used:
Cocoa butter needs 0.137 x amount in recipe
Coconut oil 0.185
Olive oil 0.134
Shea 0.128
Sunflower 0.134
What you need to do is decide how much of each oil you are going to use in your recipe, multiply it by the sapaonification value above and add them all together, this will give you how much caustic soda in total you will need to turn all of the oil used into soap. However each batch of oil varies slightly depending on growing conditions so as not to produce a soap that has any free caustic soda but has some free oil, which will make it more moisturising soapmakers superfat, this can be done 2 ways, (1) add an extra % (3-7% is normal) of any oil to the recipe but don't include it in the lye calculation or what I do is lye discount which is not add all the caustic soda needed by a certain percentage.

Sounds hard but isn't really - I want to make 1Kg soap with the following
oils: olive, coconut and shea butter and have a 5% superfat
Olive oil 450g x 0.134 = 60.3g
Coconut oil 500g x 0.185 = 92.5g
Total amount of caustic soda needed is 60.3 + 92.5 = 152.8g (round down) + 50g shea butter added usually at trace
Olive oil 450g x 0.134 = 60.3g
Coconut oil 500g x 0.185 = 92.5g
Shea butter 50g x 0.128 = 6.4g
Total amount of caustic soda needed is 159.2g but to discount divide by 100 and x by 95 to get a 5% reduction ie: 159.2 / 100 x 95 = 151.24g


03-01-2010, 02:20 PM
Hi there,

Be careful about using rose in your soaps, firstly it's extremely expensive to buy rose essential oil, and secondly but more importantly using more than 0.0004% (or something like that) is against EU regulations because it is a sensitiser, that is, if you react to it, it can make you sensitive to hundreds of other scents.

If you're not bothered about making completely natural oil, I'm not sure if the same is true if you use a fragrance oil instead of an essential oil, which would be much cheaper but is synthetic.

Good luck!

03-01-2010, 02:51 PM
wow, thanks rosamundi, that has helped heaps & it does kind of make sense,needed to read it a few times first but will definatlly be using that.

have decided to use fragrance oils, 1 as they are cheaper & 2 as i reakon theres a lot less chance of me overdosing with them.
off to do some shopping :)

07-01-2010, 08:37 PM
hi, i'm also new and have never made soap before, i got a book on soap making for xmas - The Handmade Soap Book by Melinda Coss - and this has a saponification chart in it that you might find useful.

looking forward to making my first bars of soap.