How to Make Kefir Soap

We’ve mentioned numerous times how kefir is great for the skin, from our Kefir Face Masks to our Clear Skin Tonic. One area we haven’t covered, and probably the most obvious of them all, is soap! If you’re a seasoned soap maker or just a beginner, the following recipe is incredibly easy to follow, as long as you take care to prep everything.

Why Kefir Soap?

By using kefir, your soap will be creamier and more moisturizing than a traditional water-based soap. Furthermore, kefir contains Alpha-Hydroxy Acids (AHAs) which are a group of chemical compounds that are found in a variety of organic compounds, including fresh fruit, sugar cane, and milk. They’re the key ingredient in many skincare products and can help improve the condition of skin by sloughing away dead surface cells and stimulating the production of collagen.

How to Make Kefir Soap: Cold Process and Saponification

Saponification is, in simple terms, the process that creates soap. Saponification “is the name for a chemical reaction between an acid and a base to form salt.” For our kefir soap, we used “cold process,” which is how a lot of homemade soap is made. Cold processed soaps require about 4-6 weeks to cure fully, but they’re relatively easy to make as long as you follow the safety precautions when using lye. (Seriously – this part is super important. You don’t want to end up like Tyler Durden from Fight Club.)

Notes about Soap Making with Milk/Kefir

During our soap making adventures, we learned a few tricks when it comes to using kefir (or any milk base for that matter). Similar to when you heat milk or kefir over the stovetop, you need to increase the temperature slowly. This way the milk heats up but doesn’t burn or scorch. The same idea applies to kefir soap. There are two ways to help prevent scorching. (NOTE: If you do happen to burn the kefir, your kefir-lye mixture will turn a golden color. However, this actually won’t affect the soap in any negative way.) Here’s a more in-depth breakdown about adding lye to milk/kefir.

1. Freeze the kefir in an ice cube tray.

The following recipe calls for 8oz (1 cup) of kefir. Simply measure out the kefir and pour into an ice cube tray. Freeze until frozen solid. From there, place the frozen kefir into a nonreactive bowl (glass or stainless steel). Measure out the 2oz of lye and slowly sprinkle some over the frozen kefir. Don’t pour all of the lye in at once. (We used a granulated kind, but lye can also come in flakes.) Mix the lye in the kefir and let the temperature rise. Slowly mix in more lye until all 2oz is used. The slower you pour in the lye, the less likely you will burn the kefir.

2. Ice cold kefir, pour lye slowly

Similar to the above walk-through, you can do the same with ice cold kefir. By ice cold, we mean, stick the bottle of kefir in the freezer an hour or two before you start making the soap (just don’t let it freeze solid). From there, repeat the steps above, adding the lye slowly so that the mixture heats up slowly.


Seriously folks, safety first. All of those soap making blogs out there emphasize the importance of safety gear. And we are here to tell you that they’re right – lye is no joke and can cause numerous issues if mishandled.

1. Wear long sleeves

This is in case anything splatters on you. While the actual soap batter is not as harmful as the lye itself, it can still irritate your skin.

2. Gloves

You need some chemical resistant gloves – preferably made from nitrile.

3. Safety Goggles

Yes, they may not be the most fashionable of accessories, but trust us, the last thing you want is lye in your eyes.

4. Towel or Bandana

When pouring the lye into the kefir, we made sure to tie a towel or bandana around our mouths and noses to prevent us from breathing in the lye fumes.

5. Well-Ventilated Workplace

Please make your soap in a well-ventilated area away from pets and children. Open some windows and turn on a fan or make it outside!

6. Proper Gear

Remember to use the appropriate gear when making soap. Use non-reactive spoons and spatulas (we used a silicone spatula), a waterproof thermometer, glass or stainless steel bowls. If you want to use plastic, make sure it’s the number 5 plastic.

Servings: Eight 3oz Bars


  1. Measure out the different types of oil and combine them in a stovetop safe pot. Do not put the pot over heat just yet.
  2. Take the kefir (either as frozen cubes or as very cold liquid) and place into a nonreactive bowl.
  3. Measure out the lye and slowly sprinkle a little bit over the kefir. Mix in the lye with a spatula or spoon.
  4. Once the lye has dissolved, mix in a little bit more. Repeat this until all of the lye has been mixed and dissolved.
  5. Let the lye and kefir mix sit. Now you can heat up the oils and get them to melt (don't boil - they shouldn't get hotter than 120°F).
  6. Once the oil has melted, let it cool down. Around 110°F is sufficient.
  7. Pour the oil into the kefir and lye mixture once they're both around 110°F.
  8. Use your immersion blender to mix the batter to a "trace". Essentially, the texture should be similar to that of pudding. This can take about 15 minutes of blending.
  9. Once the batter is thick, pour into your soap molds (we used silicone).
  10. Cover the soap mold with a plastic bucket and insulate the outside with a blanket or towel. You'll need to let the soap sit for about 2 days.
  11. Once the soap has hardened, you can remove from the molds and put them away to finish curing. The soap will be ready to use in about 4-6 weeks.


  • *When it comes to your fragrance, you can mix and match essential oils as you please. Some people prefer a stronger scent and others not as strong, so the amount can be toyed with.