How to Make Cucumber Soap Using the Cold Process Method
Simple cold process recipe showing how to make cucumber soap. You begin with real cucumber then blend it with creamy yogurt, natural oils, and a minty essential oil blend. The recipe makes six bars of cooling handmade soap and can be scaled up for larger batches.
This page may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.
This year was an absolutely bumper year for cucumbers! The first harvests were welcome, and we had them in all sorts of delicious recipes. I also preserved a load by fermenting and refrigerating them and also by making homemade dill pickles. There’s so much that you can do with a glut of cucumbers though, and you can bet that I used some to make handmade cucumber soap. I’m going to show you how you can too!
This is an easy step-by-step cold process soap recipe. It’s all-natural and vegetarian and includes oils such as coconut oil and castor oil. The fragrance, although optional, is cooling and minty and derived from plant-based essential oils. This cucumber soap recipe is simple enough for beginner soapmakers but if you’ve never made a batch of soap from scratch before, I’d advise that you get my soapmaking ebook and read through the beginners’ soapmaking series.
Benefits of Cucumber Soap
Handmade soap’s main purpose is to gently cleanse our skin. To make it from scratch, we just need fats, lye, and water like in this eco-friendly soap recipe. Anything extra such as essential oils, clays, and plant material is added for color, texture, scent, and conditioning. Some plants can have other beneficial properties, though, and we add them to soap to help with skin conditions. Cucumber is one of them.
We all know that cucumber slices can help soothe puffy eyes. It’s the cooling effect and high water content that helps but also anti-inflammatory compounds including flavonoids, triterpenes, and lignans. Though it’s not proven that they survive the soapmaking process (there are no studies that I’m aware of) we add cucumber to create sensitive soap suitable for all skin types. Especially red skin that suffers from inflammation.
Cucumber can also be used as a natural soap colorant. It doesn’t give you green soap but can tint your bars a greenish-beige. It can also leave your soap nearly uncolored if you watch how you add the cucumber and make sure that the soap is cooled after pouring it into the soap mold. If you’re looking for a naturally green color, you’ll need to use an additional ingredient. In this soap recipe, we’ll use French green clay to give the bars their soft green hue. Clay soap making is a natural way to color soap recipes while potentially also adding gentle oil-pulling properties to the bars.
Ways to Use Cucumber in Soap Recipes
While there are several ways to use cucumber in soap recipes, this one uses cucumber juice. You can also use the puree made from the whole fruit or cucumber peel on its own. Dried and powdered cucumber is available through specialist cosmetic suppliers and it tints soap a tan color. The peel on its own can stay a little more green-brown though. If you peel and puree the skin and add it to handmade soap, the small bits of peel can leave brownish-green flecks in your bars. It could be a lovely rustic effect but probably don’t use more than a teaspoon per pound (454g) of soaping oils to avoid the soap being too textured.
Cucumbers are almost completely water so you can replace the water content of your soap recipes with up to 100% cucumber. That’s relatively easy to do with juice but there is a risk that your final soap bars may turn out tan in color. To avoid this, I’d advise freezing the cucumber juice before adding the lye. It’s a common technique when soapmakers are working with liquids that scorch easily, such as goat’s milk.
Another way to add cucumber to soap is as puree added to the soap batter at a light trace. Cucumber puree is easily made in a blender or food processor by putting chopped cucumber in with a little water. It can be relatively chunky though, so I’d probably sieve the puree before adding it to your soap. Chunks, however small, can add unattractive splotches to the finished bars.
Cucumber Soap Recipe
- Fine mesh strainer (sieve)
- Stainless steel pan
- A bowl for measuring the liquid oils into
- Square silicone mold or another mold(s) of your choice
- Food processor or blender
To Make the Cucumber Juice
- 1/4 Cucumber, fresh about 120 g / 4.23 oz
- 100 g Distilled water 3.53 oz
- 62 g Sodium hydroxide 2.19 oz
- 62 g Distilled water 2.19 oz
- 1 tsp French Green Clay 4 g / 0.14 oz
Solid Soaping Oils
- 114 g Coconut oil (refined) 4.02 oz / 25%
- 91 g Mango butter 3.21 oz / 20%
Liquid Soaping Oils
- 227 g Olive oil 8 oz / 50%
- 23 g Castor oil 0.81 oz / 5%
After Melted Oils & Liquid Oils Are Mixed
- 1 TBSP Greek yogurt 16 g / 0.56 oz
- 50 g Cucumber juice 1.76 oz
- 1 tsp Peppermint (Mentha piperita) essential oil optional
- 3/4 tsp Citronella essential oil optional
- 1/8 tsp Fennel essential oil optional
Make the Cucumber Water
- Homemade cucumber water replaces some of the water content of this soap recipe. Making it is easy but requires a food processor or blender.
- Cut up the cucumber and place it in a food processor or blender with the distilled water. Blend until a chunky puree.
- Strain the puree through a fine mesh strainer (sieve) or cheesecloth. The cucumber juice will be a stunning green color.
- Measure out the amount of cucumber juice called for in the recipe which is just 50 g (1.76 oz). You'll have quite a bit of juice left over that you can drink as a treat or freeze to use in another soap recipe.
- You can either discard the cucumber pulp or eat it. I think it would be a nice base for a tzatziki-like dip!
Organize Your Workspace
- Before you make this cucumber soap recipe, it's safety first! Make sure to be wearing closed-toe shoes, long sleeves, eye protection (goggles), and rubber/latex gloves.
- Pre-measure all of your ingredients and ensure that your work surface is organized with all of the tools and equipment you'll need. Open a window for ventilation, close doors on pets and children, and have everything you need prepared.
Create the Lye Solution
- In a heat-proof jug, blend the French green clay with the distilled water so that there aren't any lumps. A whisk will help.
- Work in a ventilated place – near an open window or outside– and ensure that your goggles and gloves are on. Pour the lye into the clay-water and stir well. Steam, fumes, and heat are the product of water and lye interacting. Be prepared and don't breathe in the fumes.
- Place the steaming lye solution someplace safe to cool. I tend to set it in cold water in the sink.
- Please also note that this is a STRONG lye solution with equal parts lye and water. The additional water amount needed for the recipe is added later on as the cucumber juice.
Melt the Solid Oils
- Melt the solid oils (the coconut and mango butter) on low heat on your stove. When just a few pieces of solid oil are floating in the pan, turn off the heat and move the pan to a potholder. Stir with your spatula until all of the oils have fully melted.
Add the Liquid Oils, Greek Yoghurt, and Cucumber Juice
- Next, add the liquid oils to the pan of melted oils. Use the spatula to get as much of the oils in as possible as castor oil has a tendency to stick. Mix well and take the oil's temperature. You're aiming for 110°F (43°C) at this point.
- Once at this temperature, gently mix the yogurt and cucumber juice together in a bowl or jug. Pour the mixture into the pan of oils. If you're using thick yogurt that looks a bit chunky in the pan right now, you can give the mixture a whizz with the stick blender.
Balance the Temperatures
- Next, measure the temperature of the lye solution and the oils. You want both to be around 100°F (38°C) now. The temperatures don't have to be exact but they should be within around ten degrees of one another and close to that 100°F (38°C) target. When the temperatures are within range, it's time to mix the lye solution with the oils.
Bring the Soap Ingredients to Trace
- Gently pour the lye solution into the pan of warm oils. If you pour it against the side of a spatula held just above the oil it can help reduce any future air bubbles in your bars.
- Next, stir gently with your spatula for a minute or two as the mixture might thicken up quickly without the aid of an immersion blender.
- The thickness of the soap needs to become the consistency of warm pudding – when it does, the soap batter has hit 'trace' and you're ready to proceed. If it thickens to this stage, you can skip the next two steps.
- If the mixture seems very liquidy (watery) after stirring, place the immersion blender into the pan and use it to stir the mixture together gently. The head of the stick blender should be completely immersed in the liquid.
- Bring the immersion blender to a standstill in the center of your pan and then press pulse for a few seconds. Then stir gently again for a moment and repeat. Continue pulsing and stirring your soap batter until it reaches trace.
Add the Essential Oil
- Working quickly, gently stir in the essential oils if you're using them. I've included a minty-citrus blend in this recipe because it has a similar cooling yet energizing aspect as fresh cucumber on the skin. You could use another essential oil blend, though, or leave the essential out completely.
Pour the Cucumber Soap into the Mold
- Pour the pan of soap batter into your mold(s). I'm using a small 1-lb loaf mold here but you could use a small slab mold or cavity mold if you wish. Use your spatula to get as much of your soap out of the pan and into the mold. Settle the soap so that it has a flat top. You do this by gently shaking or tapping the mold.
- You could decorate the tops now if you wish. I've kept it simple and have added just a light texture by moving the edge of the spatula across the top with a tight figure of eight movement.
Cool the Cucumber Soap
- When you've finished, I'd advise that you take steps to ensure that the soap remains cool. Both the yogurt and the cucumber juice can discolor the soap if you allow this recipe to warm up and gel. Either place the molds in a cold room or put the mold in the fridge. I've done the latter with this soap, leaving it in overnight before taking it out and setting it on the kitchen counter.
Unmold and Cut Your Soap Bars
- After two days have passed since making it, you can take the cucumber soap out of the mold(s). If you've used cavity molds, proceed to the next step. For loaves, you can now cut the soap slab into bars. Use a dedicated soap cutter or an ordinary kitchen knife for this step, and how you cut your bars is up to you.
Cure the Cucumber Soap
- Now is the hard part — waiting for your soap to cure. Curing is a necessary step for all cold process soap, and it's a process that requires at least four weeks of waiting. The soap finishes saponification during the cure time, and excess water evaporates from the bars. Another thing that happens is that the crystalline structure of soap forms. The latter cannot be hurried up and is essential for a good, gentle soap.
- Cure the cucumber soap recipe by placing the bars on a layer of grease-proof paper in an out-of-the-way place. It should be airy, out of direct sunlight, and away from curious pets and kiddos. Leave them there for a whole month before using the bars.
- Once made, your soap will have a shelf-life of up to two years. The shelf life is dependant on the exact ingredients you used though — look on all of the backs of the bottles and the closest date is your soap's best-by date.
Cucumber Soap Recipe Notes
In researching this cucumber soap recipe I came across a couple of others instructing to add cucumber juice to the lye solution. I tried doing this but was disappointed by the final color. You can see one of the bars from that batch above on the right. It’s a kind of tan-brown and not very special in my opinion. It has French green clay added to it too! So make sure that the main soaping oils and lye solution are cool enough before you introduce the cucumber juice and the yogurt.
Yogurt is a brilliant ingredient for adding creaminess to handmade soap. If you’d like to omit it for whatever reason, you can replace it with distilled water. I don’t recommend adding non-dairy replacements instead.
Also, if you can’t find mango butter, you replace it with shea butter. I do love mango butter in a soap recipe though and think that it adds more conditioning and creates a slicker bar than shea butter does. If you want to try another of my recipes that uses mango butter, have a look at this hot process soap recipe. Here’s even more soapmaking inspiration for you too:
- Carrot Soap Recipe
- Pumpkin Spice Soap Recipe (with pumpkin puree)
- Butterfly Pea Flower Soap Recipe
Does the soap maintain a cucumber scent?
No, there is no cucumber scent. Usually, cucumber scent in products is a synthetic fragrance.
Waiting for this soap to cure it turned out amazing!!!! It traced quickly and waited too long to pour but I am so excited.
Thanks for your reply….will do the soap then without colourant
Thanks a lot for the recipe
I would like to make this soap, as soon as i get the mango butter , i ordered. I do not have french green clay, so I was thinking of using spirulina as my green colorant. I would like to get your opinion on this.
Thanks and greetings!
Hi Maria, unfortunately, spirulina fades and gives you a kind of muted yellow color over time. Liquid chlorophyll is a better option for a lasting green!
Congratulations for that nice receipe! I will sure try it soon. However, in this recipe, it is suggested to put the soap mold in the fridge to avoid the soap from warming up and geling that would discolor the green color. I would like to know if “avoiding the warming up and the gel stage” in any receipe can affect the cure. I am asking that because I read somewhere that the soap needs to get to a high temperature to transform the lye into soap. If you can help me with that, I would really appreciate it. Many thanks.
Hi Joanne and good question. A lot of soapmakers make soap at room temperature and many of us even go through the effort of refrigerating the soap to make sure that the color comes out the way we’d like. Soap naturally gets warm/hot during the saponification process and refrigerating doesn’t stop this from happening. It just stops the soap from getting over 170°F (77°C) and gelling and you can do it for any soap recipe. The only thing it affects is the final color and not the cure time.
Tanya I having problems I tried to make cp soap and it get clog up really fast I don’t have any problem with hp soap I wonder if it’s the fragrance oil I use olive, coconut, castor, grapeseed, oil Shea, and cocoa butter for 2lbs soap what am I doing wrong
Hi Jacqueline, when you say “clog up”, do you mean that the mixture thickens very quickly? If so, I’d guess that it’s the fragrance oil that you’re using. Some cause soap to “accelerate”, meaning to thicken up super fast!