Explaining and Preventing Soda Ash

With so many variables in soaping — from the oils you use, to the temperature you soap at to the fragrance oils you use — there are an infinite number of factors that can make a difference in your final product. Today I wanted to focus on something that we have all experienced that is a direct result of variations in your soaping recipe — soda ash. Learn more about how to prevent it and what you can do if it shows up on your soaps!

Soda ash forms when unsaponified lye reacts with naturally occurring carbon dioxide in the air.  Soda ash is a harmless, and it’s most common on the surface of your cold process soaps, but sometimes soda ash can form throughout the middle of the bars. It won’t damage your soaps, but if you have a detailed swirl or design, it may end up obscuring it. The easiest way to prevent soda ash it to spray the entire top of your recipe with 99% Isopropyl Alcohol 10 – 15 minutes after pouring the soap. Then, cover the mold with a piece of cardboard and insulate for up to 24 hours. Unmold after 3-4 days and you might find the amount of soda ash to be drastically reduced compared to not spraying and insulating (with some recipes however, no amount of alcohol or insulating will prevent all soda ash. These are simply preventive measures!).

Temperature can also play a factor in soda ash formation. If you soap too cold and too thin (if your lye and oils are less than 100 degrees F), you may find soda ash will form deep within the soap, not just on the surface. Typically, this is more common in soaps with intricate swirls that were soaped cool and thin. If you tend to soap at cooler temperatures, achieve a thicker trace before pouring to lessen soda ash formation.

This is an example of deep soda ash. In this case, veins of ash run the entire depth of the soap! This is a good example of soap that was poured cold and thin.

As an extra safeguard against soda ash, you can also decrease the water amount in your recipe by 10%, work at a lower superfat level, work at a thicker trace or even include .5% melted beeswax at thin trace to help decrease soda ash. Some soapers don’t mind the soda ash, but if you’re like me, you want your bars to be as shiny and clean as possible.

Adding .5% melted beeswax at thin trace can help decrease soda ash. Bramble Berry carries both white and yellow beeswax. The wax helps to add another barrier between the unsaponified lye and the air, effectively slowing the formation of ash. 

Three ways to clean soda ash

If you do end up with soda ash on your soaps (and if you make enough batches of cold process, you inevitably will!), have no fear. We’ve got three easy ways to quickly and easily clean your bars.

1. The first (and easiest) way to clean your soaps is with a simple cold water wash. Make sure you are wearing gloves in order to prevent any pesky fingerprints from showing up on your soap. Grab a paper towel and run your soap under cold running water and scrub the areas that have soda ash. As soon as the soda ash is gone, rinse away any lather and allow to dry on a rack

2. The most successful (and economical) way I’ve found to clean my cold process soaps in a pinch is to use old nylons to gently scrub away the ash. Once you’ve gotten a run or two and you can’t wear them any longer, cut the foot off the end of the nylons and use it in the same way you would the paper towel. This method tends to work best for me, and I don’t have to waste any paper towels. Best of all, you can use the nylon over and over again — just be sure to wash it out by hand between scrubs.

These simple techniques can drastically improve the look of your soaps, and customers are much more likely to purchase soaps that are clean and shiny with well-defined colors.

3. If you are a big batch soaper, I would suggest investing in a handheld steamer. This will reduce the soda ash on your soaps and will be invaluable in saving time in the long run. Just set your soaps on a rack and hold the steamer about 5 inches above each bar for about 20-30 seconds. The soap you see below is actually the Oatmeal Milk and Honey Mantra Swirl that happened to get a bit of soda ash on it. Taking that extra time to clean up the soda ash on your bars can really make all the difference.

By the time you are done steaming, you’ll have clean, shiny bars. Steamed bars reveal the soap’s design and bring out the colors, making it more appealing to shoppers. If you have your own strategies for getting rid of soda ash, we would love to hear what method works the best for you. Leave a comment below letting us know how you prevent soda ash!


72 Responses to “Explaining and Preventing Soda Ash”

  1. Pamela says:

    Wow! I learn something new every time I’m here. I have Never heard of the stocking trick! Thanks so much for letting us in on your tips!

  2. Amber says:

    All of my soap gets soda ash, no matter what temp I soap at, how thick the trace is, or even recipe variations. I’ve not figured out how to prevent it, although I keep planning to try spraying the tops with alcohol after molding, and always forget about it lol. Also, if I was to leave my soap in the mold even just over night, it would be entirely too hard to cut. Probably just a difference in elevation/temperature/climate since I live in west Texas. Thanks so much for all your tutorials, etc., I’ve learned so much from following Soap Queen!

    • Hi Amber!

      The easiest way to prevent soda ash is to remember to spray your soap with the rubbing alcohol before you “put it to bed”. That bit of preventative work will save you time later. I’d love to hear more about the recipes that you are working with — we’ve had recipes that we’ve left in our molds for a couple of days and never had any problem with cutting them. =)

      Happy Soaping!
      -Becky with Bramble Berry

      • Amber says:

        Hi Becky! My basic recipe is coconut oil 76 degree, Olive oil, palm oil, and castor oil. I’m not sure if it’s because I chose oils that all contribute to a hard bar or if it has something to do with the climate difference between WA and TX but the few times I tried to leave it in the mold over night it was pretty hard to cut the next day. That’s most especially true for my hot process in the crock pot batches. I’m sure I wouldn’t have as many problems with soda ash if I just remembered to use my alcohol lol. For now, most of my bars have a rustic look to them so I usually just embrace the soda ash :)

        • Amanda says:

          Hi Amber!

          I would definitely try the alcohol trick, it works wonders for us! Your recipe definitely will result in a hard bar of soap, but I don’t see that being a problem as far as soda ash is concerned. A steamer works really well to remove soda ash if the alcohol doesn’t work well for you :)

          -Amanda with Bramble Berry

  3. Amy says:

    I have found that just a quick rinse works without having to actually wipe off the top of the bars. Of course, always wear gloves to avoid the finger prints on your soap.

  4. Oh, I hate when the ash shows up in the bars! Argh! I find that spraying the ash on top of cured bars with alcohol and wiping off also works. And it dries faster than wiping off with water.

  5. Jennifer says:

    I find that ash has a lot more to do with the EO/FO I’m using than anything else. Lavender = tons of ash. Peppermint = almost none. I use the same base recipe for most all of my soaps, and generally soap at around 90-100 degrees. For me, its really really about the fragrance.

    • Good morning, Jennifer!

      Some fragrances can add a bit to the soda ash, and that is why we always suggest spraying your soap with the rubbing alcohol to prevent it no matter what FO or EO that you are using! =)

      -Becky with Bramble Berry

  6. Ornanial says:

    Rubbing alcohol and cotton ball or cotton swabs work very well also. Works really well if you have molds with raised of embeded designs. Also give my soap a great shiny polished look

  7. Traci Cornell says:

    I recently read quickly dipping your cp soap in distilled water while wearing gloves (as Anne-Marie mentioned) will get rid of Soda Ash. As I like textured tops on my soap,this makes it a bit more difficult to “wipe” them with anything. Tried this method and found it worked for 2 out of the 3 batches of soap that had Soda Ash on them.

    • Hi Traci!

      We’ve found that using a steamer for those soaps with the textured tops really does wonders for us! We are glad to hear that you have found a method that works well for you, thank you for sharing it with us. =)

      Happy Soaping!
      -Becky with Bramble Berry

  8. Anna says:

    Thanks for these great preventive tips. I’m a small batch soaper, and the last time I got ash I put the bars under a large mixing bowl with a cup of just boiled water. The bowl trapped the steam around the soap bars nicely. Most of the ash, gone.

    I am definitely writing down these preventive measures, thank you. (I hate ash.)

  9. Lyndal says:

    Thanks for these great ideas!I get soda ash every now and then. As I have just started selling my soap I’d love to remove the ash.
    I’m keen to try the nylons idea.
    Thanks again :)

  10. Lesli says:

    I agree with Jennifer that lavender EO is often a cult\prit–and it’s in a lot of my blends. The worst ash ever was when I was experimenting with wine-based soaps. It was awful!

    Beeswax does help, but it has a melting point of about 145F/63C, so you have to soap hot to keep it from beading up in the final soap–and that won’t work for some EOs I use.

    It’s all a balancing game!

  11. Melissa says:

    Thanks for the info about preventing ash. I’ve tried the alcohol and it doesn’t always seem to work. I often get ash inside the soap or else on the face within a day of unmoulding. It’s been very frustrating. Now I realise I may be soaping too cool. Thanks again.

  12. Kallen says:

    I just had to comment as I have only had ash once or twice in over 18 years of soap crafting; and that was when I first started.

    The only thing I have ever done to ensure a great batch is be absolutely meticulous in all my measurements and I always start at 87 degrees + or – 1-2 degree . I always make 35 bars at a time ; reasonably small batches for many. I occasionally made double batches of a popular soap but kept all measurements the same and mainly use essential oils. I keep fragrance oils to a minimum.
    I have no idea if all this is what keeps the bars clean ; but it works.

    I’m from N.Ca and presently live in N.W.Fl. and follow the same procedures every time. I seldom vary the recipe and do not get creative except for superfatting and colors.
    Great topic , thanks for the info.

  13. Bianca says:

    I actually learn to take water off the batch by mistake, and noticed that there was no ash!
    Thank you for your tips.

  14. Marie says:

    Hi, After I pour my soap in the molds, I cover it with plastic wrap and then put a layer of thin styrofoam on top of that., Then of course my blankets and let it rest until it is coolded down.. I do not get any soda ash. It works for me.

  15. Joan says:

    I found that the spraying with rubbing alcohol works great. I mainly do CPOP soap and after I spray with the alcohol, I cover my large flat molds snugly with freezer wrap and have found this to greatly reduce the ash as well.

  16. Cathey says:

    I have found that spraying with alcohol and curing my soaps in a closet with a dehumidifier work well, I hardly ever have soda ash, no matter what my recipe or what FO/EO I use ~ it was $$ well spent!

  17. Patricia says:

    Having a light bulb moment here.

    A while back I bought a large roaster oven at Walmart on sale for $19.95 – one that has a temperature control gauge – so that I could follow Kevin Dunn’s single-oil soap testing instructions, using the roaster to CPOP them at 170 degrees.

    I just realized I could put a rectangular cookie rack inside with a silicone baking mat on top, then put water under it, turn it on and steam a lot of bars of soap all at once.

    The steamers I’ve seen run about $70, so this is a less expensive alternative. And now that I have bought very large (and very expensive!) silicone molds that will produce 68 bars of soap, I will need a way to “de-ash” a lot at once if I run into that problem. Pure Castile soap is notorious for being an ashy soap.

    Now I’m curious as to how many bars I can fit into the roaster oven…lol. *runs off to the soap studio!*

  18. AshMac says:

    Now, I’m not saying my magnificent batch of Energy-fragranced, neon, swirled soap just got the worst case of soda ash in the history of mankind, NO! I’m just saying this post is timely. ;-)

  19. OMG I have just tried this and my soaps look AMAZING! I have made many flat bars with pretty swirls on them and was having to wipe them all with a cloth. I have a clothes steamer so thought I would give it a whirl. My soaps look shiny and new.
    I think the ashing has to do with the quality of the Sodium hydroxide and the reaction to oxygen. When I buy expensive NaOH this doesn’t happen.
    Anyway – THANKS. this was great info

  20. Heather says:

    I soap cool and pour at just emulsion instead of trace since most of my soaps have lots of intricate designs/swirls, and goat’s milk is what my customers want in their soap. I have tried covering the mold with plastic wrap (but no insulation), but the soap tends to over heat and start to sweat so I can only leave it under plastic for a few hours. I already do a 10% discount on the water, but I still get soda ash on some batches. Sometimes, only part of the batch ashes, and sometimes the ash doesn’t show up until a week after unmolding. I only use silicon molds. I don’t want to spray with alcohol since many of my customers have really sensitive skin(and eczema), and that sounds drying. I live in northern GA, and it can be really humid here when we get the tropical air from the Gulf of Mexico, but also times of very low humidity when we get the Canadian air blowing in(as you can imagine we get a lot of thunderstorms/tornados here will all the conflicting air temps and humidity levels that meet in this region of the country). Any suggestions other suggestions or tips for Southern soapers? I hate having to give my bars a “bath”, but so far that has been my only solution for soda ash. Good tip about wearing gloves-I didn’t know that the first time, and have to give around 50 bars a 2nd bath to get rid of my finger prints. :)

    • Hi Heather!

      The rubbing alcohol actually dissipates as soon as the soap has dried, so it isn’t going to cause any dryness in the soap at all. I would try it out on a small test batch to see if you like how it works.

      If you are finding that you are still getting soda ash, I would suggest adding a bit of beeswax (as listed above) and possibly investing in a steamer. When we’ve used the steamer it has really saved us so much time in the long run!

      I hope that this helps! =)
      -Becky with Bramble Berry

  21. Kellie says:

    For what its worth, I was on the internet and found yet another “cure” for surface soda ash. It involves simply spraying the tops of your soap with alcohol, let it dry for about 10 minutes and then mist with water and let dry. Worked great for me, I hope it will be helpful to others as well!

  22. Irene says:

    I’ve had absolutely no luck with spraying with alcohol 10 to 20 minutes after pouring. However, I just tried spraying with alcohol 1 day after pouring when I first take the lid off of the mold. It works like a dream. The problem is the soap being exposed to the air for the first time. Spraying at that point dries the surface of the soap and soda ash does not develop.

  23. Matthew says:

    I’ve found that my soaps have little to no ash if I first spray with alcohol just after pouring, and second, apply a sheet of wax paper over the top of the soap (gently pressing to the top of the soap adheres to the wax paper) before I insulate. I’m still learning myself.

    • Amanda says:

      Hi Matthew!

      I’m happy to hear you’ve found a technique that works well for you, thanks for the tips :). We really like spraying our soap with alcohol as well, we find it makes a big difference :)

      -Amanda with Bramble Berry

  24. […] I point you to the Soap Queen who to me is one of the authorities on all things soapmaking. Here’s an article on soda ash on soap: The Soap Queen: Explaining and Preventing Soda Ash. […]

  25. […] soda ash. It’s not harmful. But if it really bugs you, then here’s a link from BrambleBerry on how to remove soda ash from your soap. I personally like the handheld steamer method. Fast and […]

  26. Yesenia says:

    How soon after after pouring the soap in the mold can I use the steamer? Can I use right away after ash develops or should I wait till after it cures?

    Thank you.

    • Amanda says:

      Hi Yesenia!

      I would recommend waiting until you remove your soap from the mold, and give it a few days to harden. You do not need to wait until it fully cures, but I recommend waiting until it is firm enough to cut :)

      -Amanda with Bramble Berry

  27. Jackie M says:

    Hello, I have a few questions about soda ash in CP soap:

    1. If I use mica previously mixed with oil in swirls on top of my soap. Should I put mica, sparkles etc… before spraying with alcohol or afterwards?

    2. If I invest in a hand held steamer. Is it just a clothes steamer? Is there a certain brand that is better? When do I steam? Is it after cutting bars, 24 hours later, or longer?

    Sorry for the loaded questions, thanks for your help and time.

    • Amanda says:

      Hi Jackie!

      I would recommend spraying your soap after you have placed your mica/oil mixture on top. We use a clothing steamer that we purchased from Amazon. Nothing too fancy :). I would recommend steaming after you have removed your soap from the mold (after 3-4 days). You can steam it before you cut or after, doesn’t really matter! :)

      -Amanda with Bramble Berry

  28. Jackie says:

    Can you steam over mica or sparkles or piped soap? How long to do hold the steamer in one place to prevent soda ash?
    Thanks so much :)

    • Amanda says:

      Hi Jackie!

      You can definitely steam over soap that has sparkles or mica on top, you can see us doing so in this Instagram video!


      The purpose of steaming your soap is to remove any soda ash that has occurred. When steaming your soap, you will actually see the soda ash start to go away. I don’t hold the steamer in one place for too long, on average it only takes a few minutes to steam a whole batch of soap :)

      -Amanda with Bramble Berry

  29. Monica says:

    I’ve been soaping for few years now and sell at local farmers markets here in Australia. I was at my wits end with soda ash. Every batch I made ended up with the dreaded ash. Needless to say I’ve tried many different techniques to prevent/remove it.

    Spraying with rubbing alcohol didn’t work.
    Soaping at all different temps didn’t work.
    Soaping with beeswax gave the soap feel and texture I wasn’t happy with and didn’t work.
    Covering with plastic wrap straight after pouring is only good for flat tops and also left wrinkle marks but it did work.
    Steaming does remove ash.
    Washing the bar also removes the ash but gave the bars a ‘used’ look.

    I texture my tops and have finally found a solution that works for me. Yay!

    After pouring I spritz the top with rubbing alcohol.
    I don’t insulate and let the soap sit for about an hour and a half to two hours until its nice and firm
    I then gently cover with plastic wrap and press it around the edge of the silicon mould. As the soap is hard there are no wrinkles or marks left on the soap from the wrap. It’s also not pressed firmly to the top of the soap but really only touches the tops of the textured peaks.
    After 24 hours I unmould and put a fan on the loaf for about an hour, then cut and voila – NO ASH!!! :)

    Hope this helps someone.

    • Amanda says:

      Hi Monica!

      Oh that’s such an awesome tip, thanks for sharing! I’m glad you were able to find a technique that works well for you. Good thinking with the plastic wrap! :)

      -Amanda with Bramble Berry

  30. Saahaar says:

    Good Article! Now I know I have a fight with soda ash on my soaps!

  31. lyn says:

    Please help! I’m new at soap making and have been faced with this issue. While my soaps are curing they sweat and when I rub the bars it smells horrible on my hands. It’s smells like a vinegar maybe ammonia smell. I don’t use any milks in my bars. Will this go away.the bars have already cured on average of 3-4 week and still are.

    • Kelsey says:

      Hi Lyn!

      Oh no! Do you mind if I ask what’s in your recipe? What fragrance and color? Also, how much lye liquid are you using?

      Let me know and we’ll get this figured out! :)

      -Kelsey with Bramble Berry

  32. Winnie says:

    I’m new at soap making too and all my soaps have developed soda ash. Incredibly… the soda ash on my soaps are really really deep! Steaming does not work… running it under water and rubbing gently does not work (because the soda ash runs so deep)… the only thing that works is cutting the soda ash off with a knife! But then I’m losing soap :(

    What else can I do to remove the soda ash?

    • Kelsey says:

      Hi Winnie!

      If you’re getting soda ash in your bars, there are a couple of steps you can take to prevent it!

      You can decrease the water amount in your recipe by 10% or work at a lower superfat level.

      You can also pour your soap when it’s at a thicker trace. Adding .5% melted beeswax at thin trace helps as well. :)

      -Kelsey with Bramble Berry

  33. Leigh says:

    I’m new to soaping, but luckily have made some (I think) very pretty bars of soap. The problem I’m having is not soda ash (yet) but fingerprints! I’ve worn gloves but they still leave marks. How can I a) prevent fingerprints and b) remove them if they happen?

    I’m sure there is the simplest answer. I just can’t figure it out. Thanks!

    • Kelsey says:

      Hi Leigh!

      Fingerprints can be pesky, but there are easy ways to prevent them!

      To prevent finger prints, place a piece of freezer paper in between your fingers and the bars. That will prevent any transfer and keep them nice and clean.

      As for removing them, that can be tricky. Depending on how deep the prints are, they may stick. I would recommend spritzing your bar with 99% isopropyl alcohol and rubbing them with a paper towel to see if that helps. :)

      -Kelsey with Bramble Berry

      99% isopropyl alcohol: http://www.brambleberry.com/Isopropyl-Alcohol-99-16-oz-P5682.aspx

  34. Patricia says:

    My question is:what if you dont use soda ash at all,what will happen?

  35. Lynnie says:

    Please help me! I’ve made 3 batches of soap – each with the exact same recipe and superfat level. The first batch I made in a silicone loaf, I prefer the look of none gelled soaps so I put it in the freezer overnight. I took it out in the morning and let it sit at room temp for a couple of hours, then unmolded. The soap turned out great although I got eager and cut it too early. the knife stuck and it’s a bit uneven, haha. but other than that it’s fine and curing nicely.
    So I made my second two batches back to back in your square individual silicone mold. I put them in the freezer. but this time I unmolded them immediately after removing them from the freezer. They were hard enough and looked beautiful and glossy upon unmolding and I loved the look of the non gel.
    I noticed a couple hours later they were covered in little droplets of oily sweat (it looked like your picures of “glycerin dew” except more yellow. but this isn’t m&p…) – the bottoms had this little layer of yellow oil that turned that side a little orange. This had me worried so I turned a fan on and directed it at the soaps on the rack. Today the soaps are covered in ash and they seem darker than before almost as if when I took them out of the fridge they started to gel on their own?

    So my question is what happened to my second two batches? Did I not leave them in the freezer long enough (i left the first successful batch in longer) and did unmolding them immediately after removing them from the freezer cause this oily sweat that dried into ash? should I do what I did the first time- leave it in the freezer for 24 hours take it out and leave at room temp for a few hours, and then unmold? and then they won’t sweat? have you ever heard of or experienced this? I hear about soda ash on tops of soaps before unmolding but never hear about sweating after unmolding before the ash develops. or having ash all over the soaps on every side. I sprayed with alcohol also before putting them in freezer just like I did with the first successful batch.
    my other question is can soaps begin to heat up and gel after un molding at room temp after being in the freezer for about 12 hours?
    and my last question is is my soap usable?
    thank you for your time!

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