Oatmeal Soap Recipe (Cold Process)

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Oats are a soothing skincare ingredient perfect in soap recipes for sensitive and inflamed skin. There are a few ways to use them, so let me show you a couple of techniques in this all-natural oatmeal soap recipe. It’s from scratch using the cold process method and includes a touch of honey added at the right time to create a creamy color and boost the lather. In addition, I’ve included guidance on ways to use rolled oats, quick oats, oat milk, and colloidal oats in soap making. You could use just one method or several to make any recipe an oatmeal soap recipe!

Oatmeal Soap Recipe - How to make oatmeal soap using rolled oats, oat water, and a touch of honey for a creamy color. This recipe is from scratch and uses the cold process method #soaprecipe #soapmaking #coldprocesssoap

Oatmeal is a wonderful soap additive that is not only easy to source and inexpensive but that has incredible skin benefits. I remember getting a terrible sunburn many years ago – it was one of those early spring days that I spent working all day in the garden! Nothing could soothe the pain and inflammation except for a warm bath made with oatmeal. A cup of it in the water was enough to relieve the pain and help me to relax. That’s because oatmeal contains several compounds proven to reduce inflammation. The main one is called Avenanthramides, which reduce the skin’s production of cytokines. These are proteins secreted by the immune system to affect other cells. In the case of inflammation, to tell cells to be inflammed and sore. Oatmeal also contains lipids and polysaccharides (starch) that restore your skin’s moisture balance.

All of this makes oatmeal a humble but mighty skincare ingredient. You can use it in lotions, skin cream recipes, facial scrubs, bath fizzies, and even handmade soap. Although soap is a wash-off product and spends less time on your skin than other products, oatmeal can still make it gentle and creamy.

Ways to Use Oatmeal in Soap

Getting those creamy skin-loving oats into your soap is easy and there are a few ways to go about it. The simplest way is to sprinkle them on the tops of your bars as a decoration. They may add light exfoliation this way, but it’s really more about presentation. The next way is to stir oats into soap at emulsion or trace. All sizes of oats can go in this way but finely ground colloidal oatmeal is the least noticable. Larger oat pieces can act as light exfoliation when added this way and can also look interesting in bars cut from loaves.

Three bars of oatmeal soap with rolled oats as top decorations.
Rolled oats as a simple and rustic soap decoration.

I used to make a lavender soap with oatmeal to sell using this method some years ago. I swear that it held its fragrance much better than standard lavender soap bars! Maybe the essential oil gets partially absorbed by oatmeal which then slow releases it over time. Lastly, you can blend oat milk or an oaty water into soap recipes. This adds all the benefits of oats without having to necessarily have physical pieces of oatmeal.

Oat Milk in Soap Recipes

Milk, such as goat milk, has long been used in natural soap recipes for its creamy feeling and benefits for sensitive skin. Not everyone can use dairy milk in soap, though, for reasons ranging from ethical preference to allergies. In that case, we can get some of the same benefits of dairy milk soap from vegan alternatives such as coconut milk and oat milk.

Frozen cubes of milk
Freeze oat milk to stop it from scorching in the lye solution.

Adding oat milk to soap recipes is much like adding dairy milk – you use it in place of some or all of the water called for in the recipe. Just as when using dairy milk, you have to be careful of it scorching when it comes into contact with the lye, though. For this reason, there are two methods to add oat milk to soap recipes. For a full water replacement, freeze oat milk and stir the frozen cubes with the lye crystals. When you mix the frozen oat milk with the lye, it melts but the temperature doesn’t get very high.

Pouring milk into the warm oils in a pot.
You can also pour oat milk into the warmed oils before adding the lye solution.

The easier way to add oat milk to soap recipes is with a partial replacement. Lye needs at least it’s own weight in water to dissolve and make a lye solution. So you use only that much water, and replace the rest of the water called for in the recipe with oat milk. You add the oat milk by pouring into the warm oils before adding the cooled lye solution.

Oatmeal, Rolled Oats, and Colloidal Oats

There are quite a few different oat products out there and it can be confusing choosing one for soapmaking. The good news is that, as long as the product is 100% oats, you can use it! When oats are harvested and processed, they’re rolled, cut, and ground into different grades. Old-fashioned rolled oats are the largest flakes and are my favorite type for using as oaty soap decorations. Mixed into the soap batter, they can also work as a gentle skin exfoliant. Quick oats are a bit finer and cook down to a porridge consistency. They, and colloidal oatmeal, will make your lye solution gloopier than rolled oats. That’s perfectly fine, though, and is just more of the starch in the water. Make sure to scrape all of it out of the jug when adding to the oils.

Three different types of oats laid out on a cutting board: rolled oats, quick oats, and colloidal oatmeal.
Oats come in different grades, but all can be used in soap recipes.

Another fantastic way to make oatmeal soap is to use colloidal oatmeal. You can barely feel this fine oatmeal when washing with soap but it adds all the same goodness as more typical types of oatmeal. Maybe even more since it’s larger surface area means more opportunity for extraction. It may be more expensive than ordinary oats, but the only difference between colloidal oats and rolled or quick oats is how fine it is. You can make it at home by putting oatmeal in a coffee grinder and pulsing it until it’s a fine powder. Colloidal oatmeal and oat flour are both finely ground oats but the difference is that the latter has had the bran removed.

Before and after of rolled oats made into colloidal oats in a coffee grinder.
Grind oatmeal finely, and what you get is colloidal oatmeal.

Gluten-free Oatmeal Soap

If you have a celiac in the family or you want to ensure that your products are safe for customers who do, consider using gluten-free oatmeal. Oats are naturally gluten-free but are often processed in places that can have gluten contamination. Though gluten needs to be digested to have a celiac effect, it’s better to be safe than sorry! Gluten-free oats are becoming easier to find in supermarkets, but if you’ve not seen it, you can purchase it online.

Troubleshooting Oatmeal Soap

Feel free to use one or several of the methods described above when making oatmeal soap. However, be aware of a few things. First, too much oaty material in the bars may feel too scratchy for some people. I recommend using up to one Tablespoon of oats per 454 g (1lb) batch of soap. You can use more, but that might affect how the soap lathers and feels on your skin.

Slightly thickened lye solution with oats floating in it.
Quick oats mixed into the lye solution can thicken it slightly or make it into a paste.

Another thing is that soap made with oat milk can heat up after being poured into the soap mold. If you’d like to avoid partial gels, consider taking steps to stop the soap from heating up. That may mean refrigerating it or using cavity or slab molds, rather than loaf molds. I’d do this anyway if you want to have lighter colored bars. Personally, I like a bar of oatmeal soap to have a lovely oaty color, which is why I use honey in the recipe below.

Making the lye solution with oat milk, oaty water, or oats in it may lead to it thickening. It could be ever so slight or full on goop. If this happens to you, don’t worry, it’s perfectly normal. Don’t strain the lye solution through a sieve, if that was your plan, and scrape all of it into the oils. A whizz and blitz with the immersion blender and it will be like it never happened.

A woman washes her face with soap while looking in the mirror.
Oatmeal is ideal for washing sensitive skin.

Lastly, using oat milk or an oaty infusion in soap may give you blue bars! This only seems to happen when using loaf molds, and the light blue color fades rather quickly. It can be alarming to see at first, though. Soap-making can be full of surprises!

Sensitive Skin Soap Recipes

Oatmeal Soap Recipe - How to make oatmeal soap using rolled oats, oat water, and a touch of honey for a creamy color. This recipe is from scratch and uses the cold process method #soaprecipe #soapmaking #coldprocesssoap

Oatmeal Soap Recipe

Lovely Greens
This natural oatmeal soap recipe uses an oatmeal infusion, oat pieces, and honey to give the bars a creamy color. It's a cold process soap recipe that makes 4-6 bars. Technical information: 1lb / 454g batch — 5% superfat — 33% lye concentration. There's a full DIY video at the bottom of the recipe.
Author Lovely Greens
Cost 10



Lye solution

Solid oils

Liquid oils

After Trace


Prepare Your Workspace

  • Prepare your workstation with your tools, equipment, and safety gear. Wear long sleeves and wear rubber gloves, eye protection, and an apron. Carefully pre-measure the ingredients. The solid oils into the pan along with the honey, the liquid oils into a jug, the water into another heat-proof jug, and the lye and oatmeal (for the lye solution) in separate containers.
  • Set out your mold and ensure you have everything you need laid out. Being organized at this stage will help you to successfully make soap.

Make Oatmeal Soap

  • The first step is to dissolve the lye (sodium hydroxide) crystals in the water. In an airy place, outdoors is best, pour the lye crystals into the water and stir well. There will be a lot of heat and steam so be careful. Try not to breathe it in. After they're dissolved, stir in the oats.
  • Leave outside in a safe place, or in a shallow basin of water to cool. If you use rolled oats, the liquid will only slightly thicken as the starch is released. It may be thicker if you use porridge oats (quick oats) or colloidal oats. Don't worry if this happens.
  • Melt the solid oils and honey on low heat in a stainless steel pan on the stovetop. Leave it on the heat until all the oils are melted and you notice the honey sizzling a little at the bottom of the pan. This sizzling is the honey slightly caramelizing which will help the soap have a creamier finished color.
  • When melted, remove from the heat and set on a potholder. Pour in the liquid oils. If you have the olive and castor oils in the same container, stir them together first before pouring into the pan. Castor oil is thick and sticky and it's easier to pour when mixed with a lighter oil.
  • Measure the temperatures of the oaty lye solution and the oils. Aim to cool them both to be 100°F (38°C) or just below. 
  • Pour the lye solution into the pan of oils. Don't use a sieve unless you want to remove the oatmeal pieces from the lye solution. If your lye solution is thick and gloopy, don't use a sieve at all. Just pour/scrape it all into the oils.
  • Dip the immersion blender into the pan, and with it turned off, stir the mixture. Next, bring it to the center of the pan, and with both your hands, hold it on the bottom of the pan and stick blend for just a couple of seconds. Turn it off and stir the soap batter, using the blender as a spoon.
  • Repeat until the mixture thickens up to 'Trace.' This is when the batter leaves a distinguishable trail on the surface. The consistency and look of it will be like thin custard. It will quickly thicken up to a medium trace, which is more like pudding, which is actually better for this recipe. A medium trace will help suspend the oatmeal pieces in the soap. A thinner consistency may lead to them falling to the bottom of the mold.
  • Stir in the essential oil, if you're using it. Mix thoroughly but quickly. Essential oil adds scent to your soap, but it's an optional ingredient and you can leave it out if you'd like unscented oatmeal soap.
  • Still working quickly, pour the soap into the mold(s). Give it a tap to settle it and release air bubbles. If you wish, you can sprinkle rolled oats over the top. The color of the soap will be more golden right now than what it will end up.
  • If you're using cavity molds or a slab mold, you can leave it on the counter with no other covering. In the case that you're using a loaf mold, I'd recommend that you either take steps to ensure it gels completely or doesn't gel at all. The honey and the oats in the soap will cause it to heat up a bit after its in the mold. It may form a partial gel in the middle if you leave it on the counter uninsulated.
  • Once 48 hours have passed, take the soap out of the mold and cut it into bars using a soap cutter or kitchen knife. Cut the loaf from the bottom to avoid dragging the decorative oatmeal pieces on the top through the soap. Otherwise, they may leave drag marks as you drag them down the bars with your knife.
  • Cure it for at least 28 days. Curing means leaving the bars spaced out on a protected surface out of direct sunlight and in an airy place. This allows the extra water content to fully evaporate out. Here are full instructions on how to cure soap.



Once made, your soap will have a shelf-life of up to two years. Check the oil bottles that you’re using though — the closest best-by date is the best-by date of your soap.
Are you a beginner soapmaker looking for more guidance on how to make handmade soap? Enroll in the Natural Soapmaking for Beginners Online Course to get up to speed quickly. You’ll learn all about soap ingredients and equipment and be guided through step-by-step soap recipe videos.
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  1. Hi Tanya,

    I’m making this now and my oats have turned a bit orange/red in sections in the lye/water liquid. Do you know why? I did leave the metal spoon in there for awhile.


    1. This sometimes happens and I think that it’s the sugars in the oats reacting with the lye. It’s nothing to worry about, though, and the final color shouldn’t be affected.

      1. Thank you, it seems ok :)
        I have another question, when I add dried flowers during trace they turn almost black once it’s ready to remove from the mould. Do you know why the petals don’t keep their colour? I added very small yellow flowers.

  2. Wow I can’t wait to try making these, I’ve never made oatmeal soap. I wanted to thank you for always being so generous with your recipes and a good teacher by using such clear instructions! I’m a little afraid to try the frozen oatmilk method, but will go back and really review your article and maybe give it a whirl.

    1. You’re most welcome, Mary! The end recipe doesn’t include frozen oat milk but the technique is described for anyone who would like to make soap that way.