Soda Ash only happening when extra ingredients added

Discussion in 'Lye-Based Soap Forum' started by Happy2018, Jan 29, 2018.

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  1. Jan 29, 2018 #1

    Happy2018

    Happy2018

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    Soda Ash only happening when extra ingredients added.
    HI,
    I've been making small batches of a very basic soap, maybe 6 -7 of them, to get the hang of it, and everything is turning out fine.
    Then I added some lye to the kelp water, ( 1 batch) and then lye to the elderberry (strained) water (a second batch), and both came to a light trace, but now both have soda ash on them.
    I should also add that they were both (lye water) the same temp as the oil before mixing the two together.
    Has anyone else had this similar experience?
    The recipe I have been using is this:

    Screen Shot 2018-01-12 at 3.03.10 PM.jpg
     
  2. Jan 30, 2018 #2

    Jeanea

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    The extra additives in my experience has nothing to do with it. Sometimes soap just ashes. To try to prevent this, you can spray your soap with 91% rubbing alcohol after you've poured and designed your soap. You can also use the alcohol to remove the ashed from the finished soap. Hope this helps.
     
  3. Jan 30, 2018 #3

    earlene

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    How many batches of soap have you made? I've made many many batches in the past three years and I've had soda ash on many soap without additives. According to Dr. Kevin Dunn, 'soda ash appears where lye meets air' so it's not the additives that are causing the soda ash. It's the lye and the air having a chemical reaction to each other. Covering the soap tightly so it doesn't meet as much air is one way of reducing the reaction. But it's not the only thing you can do to help prevent it. Some folks say gelling helps prevent it, but it can still happen. Some say reaching a thicker trace before pouring the soap helps prevent it. Maybe, as that can help make sure you reach gel. But I have had soaps I CPOP'd get soda ash. If you make a soap with too much lye, you will get more soda ash, but not all soap that gets soda ash has too much lye.

    Here is a good article on the topic:
    https://www.soapqueen.com/bath-and-...nd-tricks/explaining-and-preventing-soda-ash/

    Incidentally, Sodium Bicarbonate Carbonate (Arm & Hammer Washing Soda) is also called soda ash, so is it the same chemical that we call soda ash that forms on soap? I don't think it's the exact same chemical, but it could be confusing.

    Edited to correct an error I made in using the wrong word (even though I knew the correct word and had just read Kevin Dunn's Caveman Chemistry site where he happened to mention that Sodium Carbonate is also known as soda ash and that Washing Soda is in fact Sodium Carbonate.) So anyway, my error in typing the wrong word and not properly proof reading my own composition to catch my own error.

    Thank you, DeeAnna for bringing that to my attention. I hate it when I make an error like that and it stays out there for all to see. But at least now I can correct it AND show what was in need of correction. ;)
     
    Last edited: Feb 1, 2018
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  4. Jan 30, 2018 #4

    SaltedFig

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    @Happy2018

    You are working with a low lye concentration (of just over 27%), which is fairly high amount of water.

    The high water means that the NaOH can easily travel around during saponification and curing, so there will be many opportunities for it to reach the air and react with that, instead of your oils.

    Your recipe isn't a super fast one, so unless you have something that accelerates it, you might be able to reduce your ash quite significantly just by increasing your lye concentration (to about 30% to 33%).
     
  5. Jan 31, 2018 #5

    shunt2011

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    I agree with SaltedFig. The higher the water/liquid amount the more likely it is for ash. I have found that if I give my soap a good spritz of 91% alcohol and leave it covered until completely cooled I’m less likely to get ash. I do check it a few times to check on gel to make sure it doesn’t get too hot.
     
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  6. Jan 31, 2018 #6

    DeeAnna

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    Sodium bicarbonate is baking soda.

    Sodium carbonate (no "bi" in the name) is soda ash, aka washing soda. It's the "ash" on soap.
     
  7. Jan 31, 2018 #7

    IrishLass

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    Right here, silly!
    It's very rare that I get ash. On those occasions when it does happen, it's only a very light dusting that easily washes right off with a little water and a cloth, or alcohol and a soft toothbrush....or vice-versa.

    For what it's worth, I soap on the warm side (110F-120F), use a 33% lye concentration, pour at med-thick trace into an insulated mold, and encourage full gel by (gently) CPOPing it in my oven. By 'gently', I mean that I preheat my oven to 110F, place my insulated soap inside and turn the oven off immediately. Then I shut the oven door and forget about my soap for the next 18 hours or so.

    I would say that 99% of the time my soap fully gels. The rare 1% is when I get a partial gel, about 1/8" shy of a full gel.

    The times that I get ash seem to coincide with those times that I either get a partial gel and/or when I unmold when the soap hasn't fully cooled all the way down.


    IrishLass :)
     
  8. Feb 2, 2018 #8

    Happy2018

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    I apologize for not posting sooner, something happened and I couldn't see the site for a couple of days, and now its all changed up.




    Thank you for the suggestion.





    Thank you so much for that and for the link, so that I may understand more.





    I wasn't aware that I was working with a low lye concentrate, I had wanted to have time, to work with the soap, and I am a slow mover. The recipe that I am using was modified not by me, to not use palm oil and came with that lye concentrate.

    If I increase the lye concentrate that will mean it also sets faster when it reaches trace?

    Thank you
     
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  9. Feb 2, 2018 #9

    Happy2018

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    Thank you, this seems like an awesome process!
     
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  10. Feb 2, 2018 #10

    SaltedFig

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    The default way of calculating water in the online calculators can lead to high water recipes where it is not needed (or wanted), unfortunately.

    If you increase your lye concentration from around 27% to 30-33%, you might notice that it comes to trace slightly faster, and it continues to thicken slightly faster, but it won't be by much. If you are not sure, start at 30% and see how you go. I suspect you might like it.

    The benefit you will get will be a more stable reaction (you will be less likely to get separation in the mold), the water amount is very easy to calculate (at 33%, water is roughly 2 times the weight of the hydroxide) and if you do add a tiny bit of extra water (as you might do if you use water with your colors or clays) you won't cause your soap to fail (and so you won't need to worry about adjusting your recipe). It will also reduce (and potentially resolve) your ash problem.

    If you follow IrishLass's tips (which include a 33% lye concentration), you'll do just fine with your recipe.
     
  11. Feb 2, 2018 #11

    ngian

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    Hello
    As others already pointed out some of the ways that soda ash can be minimized, I have gathered a list of parameters that can affect the amount of soda ash on the top of the soaps and these mostly influence the speed of saponification (how soon NaOH will react with oils before water grabs it and brings it in contact with carbon dioxide in the atmosphere).

    1) Use less water for creating your lye solution. Always calculate water amount in relation to NaOH that the recipe needs. An experiment I did once showed that less water minimizes or even doesn't create a hint of ash as the less water shortens the saponification time while there is less water for the soap bar to evaporate during its curing time:

    [​IMG]

    The left orange soap is made with 2,5 | 1 water to NaOH ratio (28% lye concentration) and the right green soap is made with 1,5|1 water to NaOH ratio (40% lye concentration) while all others being equal.

    2) Use more heat to fasten the saponification reaction. CPOP after molding or mix the ingredients (lye and oils) in warmer than normal temperature. Some people say that when they use beeswax in a recipe then there is no soda ash on their cured soaps. Well I think that the higher than normal mixing temperature that beeswax needs is to blame for that.

    3) If the recipe has higher amount of fatty acids that saponify faster than others then soda ash is also minimized. Hard oils tend to saponify faster than soft oils AND old oils (hard or soft) that have higher amount of free fatty acids also saponify faster than fresh oils.

    4) Finally I have seen that spraying with rubbing alcohol just after molding the soap seems to also help minimizing the phenomenon. I have seen that the alcohol creates a skin of soap just right after the spraying on the top of the soaploaf as alcohol is a known catalyst in the saponification reaction. That early soap skin on the fresh soap paste seems to somehow block the NaOH's most of the reaction with the air even while the curing process. This is my non academic point of view on that.

    Also if someone will use a fragrance that will accelerate then this also helps NaOH to react faster with oils rather than with the air.

    Nikos
     
    Last edited: Feb 2, 2018
  12. Feb 2, 2018 #12

    earlene

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    Thank you for your write-up, Nikos. I especially find your hypothesis as to why the alcohol helps prevent soda ash to be VERY helpful. I like to have a better understanding of the 'why' when doing something or recommending it to others. And what you say makes so much sense to me. I have never put that together about the alcohol before.
     
  13. Feb 3, 2018 #13

    DeeAnna

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    Useful advice, Nikos! Thank you. I'm saving your post for future reference.
     
  14. Feb 3, 2018 #14

    Happy2018

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    Thank you!


    I am making notes of advise, and will be trying this.:):):)
     
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  15. Feb 3, 2018 #15

    Happy2018

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    Thank, with each reply I have learned more, and appreciate the explanation, its awesome to be able to understand they 'why' of things, :):):). and will enjoy experimenting more!
     
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