Making liquid soap is easy!
Unlike cold process soap, it is ready to use immediately after the process is complete. Our liquid soap is made via hot process. This method completes the saponification very quickly. If you have cold process soapmaking experience, so much the better!
We use potassium hydroxide to saponify the oils in liquid soapmaking. In bar soapmaking we use sodium hydroxide. The potassium hydroxide molecules are larger than the sodium hydroxide molecules. It is this size difference that enables the potassium hydroxide to maintain a liquid state.
Safety rules in liquid soapmaking are the same as in cold process soapmaking. When your soap is cooking, it will still be very caustic and sticky, especially at the beginning. Avoid skin contact. Keep vinegar neat to hand and douse skin immediately after contact. Rinse thoroughly and repeat as needed till burning stops.
Never, Never, Never use anything other than stainless steel if you are using metal containers. ALUMINUM WILL CORRODE!!
Equipment is simple–much the same as cold process soapmaking. The major addition is a double boiler in which to cook the soap. The inner pot MUST be made of stainless steel. The outer pot may be made of any material, but the inner pot must fit inside completely. This arrangement allows for a faster, more even cook. Size your pots to ensure that the soap batch fills one-third or more of the soap pot. An eight quart pot will process 125 oz. of oils — enough to make between 4 and 5 gallons of liquid soap.
- double boiler with inner stainless steel pot
- 5 gallon bucket with pour spout lid
- blankets or towels for insulation
- a stick blender a strong, stainless steel blade
- plastic (nylon) spoon
- plastic or stainless bowls to weigh lye and oils
- rubber gloves
- liquid measuring cups
- optional – sieve and cheesecloth
How to Process
Review safety instructions. Click here.
Put required amount of distilled water into soap pot. Weigh potassium hydroxide and add to water. Since potassium hydroxide generates more heat than sodium hydroxide, it is important to insulate the bottom of the soap pot. The water will approach boiling. Set aside to cool, while you prepare the oils. Do not add goat’s milk at this time. It will burn and ruin the soap.
Weigh oils and heat to 120-130F, 50-55C. The water & potassium hydroxide temperature must be approximately the same as the oil temperature before you combine the two phases.
The next step is the same as cold process soapmaking. The big difference is in how long you hold the trace process. In liquid soapmaking, we blend the soap base well beyond trace.
Combine the oils with the lye/water mix and mix for 2-3 minutes with the stick blender. Allow to rest for 5 minutes and blend again for another 2-3 minutes. Allow to rest for about 10 minutes, occasionally checking consistency with the spoon. Continue the blend and rest cycles until the soap reaches trace. Trace occur in this soap as it thickens and holds dropped droplets on the surface for just a second.
NOTE: Do not become concerned should the soap partially or completely seize. This will be corrected during the cooking phase. Your current objective is a heavy trace. You may even have a bit of free (unsaponified) oil, at this time. If making goat’s milk liquid soap, add the goat’s milk now. The heat and the lye strength have now been reduced to the point that the milk fats and proteins will not be damaged. Use a stick blender to insures a thorough mix. Your mix will become brown. We recommend using 12 oz. can of concentrated goats milk per 125 oz. of oil.
1) Lye content – A lower lye discount is usual for liquid soaps, than for cold process soaps. 3 – 4% is normal, and will provide a transparent liquid soap. Higher oils contents will cloud the soap. Higher lye contents may require pH adjustment after saponification. This will reduce the soap’s efficacy.
2) Palm oil and other high stearic acid content oils are not necessary to ensure a good soap. Shea, mango and cocoa butter should be kept low (below 2%). Wax contents, including jojoba, should be kept at less than 2% to ensure transparency. The fatty alcohols in waxes do not dissolve and form a waxy, milky layer that floats at the top of the soap mix.
Place the inner pot in the double boiler. Fill outer pot with water until it reaches the same height as the inner pots’ soap level. Heat to boiling. Keep outer water level constant. Add water as necessary. Check the soap every 15 minutes, stirring well. At this point, you should see opaque soap curds and free oils.
Continue mixing these together. As the cooking progresses, the free oils will absorb into the soap mass. After the first half hour of boiling and stirring, you can check a bit less frequently. As the soap cooks, it will convert to gel phase. It usually takes 4-8 hours of cooking to finish the soap.
When the soap is ready, it will be transparent, with no free liquid left. Be sure to turn the soap over completely from the bottom. The soap mass can trap liquids on the bottom, so turning it over is very important. Finished soaps will remain transparent on a spoon after it cools. When the soap is finished, it must be dissolved in water to be used as a liquid soap.
Boiling distilled water is needed for this step. Remove the soap pot from the double boiler and insulate well to retain heat.
Clean outer pot and use to boil the distilled water for the final dilution. Be very careful during this operation. Soap is at 212 F and will stick and scald if it contacts skin.
Boil 2.5 gallons of distilled water per 125 oz. oil weight in the soap base. When water reaches boiling, transfer the soap base to the empty 5 gallon plastic bucket or pail and pour the boiling water over it. Stir with a big clean spoon. Mix a little — you’re not after smoothness here — just break up the soap mass.
Cover with lid and insulate the bucket completely — including the bottom. The soap mass will gradually dissolve. Heat speeds the process.
Open bucket and stir once an hour for the first few hours, then once every 4-8 hours, until base is smooth. This may take several days. Add more boiling water if you still have undissolved soap after 2-3 days.
Once soap base is completely smooth, it’s ready to use. Test pH with a pH test strip. Add up to 3% essential or fragrance oils, if desired. Some goat’s milk soaps will develop a sludge at the bottom. Remove by filtering through cheesecloth placed in a sieve. Strain and decant. Add scent as desired.