ReBatching, or hand milling, is a technique used by various soap makers. The commercial process is sometimes also referred to as French milling.
In ReBatching, specially purchased or previously made soap is finely grated or milled and mixed with a liquid; into which the soap shavings begin to dissolve. It is then heated at a fairly low temperature until the mass is more or less homogenous. When it becomes translucent and reaches a thick, gel-like consistency, it is spooned or piped into moulds and allowed to harden.
ReBatching is a great way for you to experiment with soap making while bypassing many of the more complex steps in making handmade soap so it can be ideal for specific projects. ReBatching is often used as a way of adding ingredients that can not withstand the high temperatures or alkaline environment of cold process or hot process soapmaking, such as volatile essential oils, or those that discolour (lavender buds).
Choosing the appropriate rebatch liquid also affects the character of the finished soap; goatsmilk can be used to give the soap a smooth, creamy consistency as well as coconut milk but more often han not just plain old tapwater will do fine. Rebatching can also be used as a way of salvaging soap that cracked, curdled or separated while being made.
Basic supplies for rebatching soap:
- Soap (noodles or bars) or you can use our Rebatch base instead
- Stainless steel or glass bowl
- Cheese grater
- Water or coconut milk
- Small saucepan, double boiler, crockpot
- Oven bag
- Wooden spoon (may affect essential oil)
- Additive (essential oil, natural fragrance oil, colloidal oatmeal, jojoba beads, lavender, etc.)
- Plastic moulds
- Baking rack
Instructions for ReBatching soap noodles:
1. Crush the soap noodles or grate soap so that you have at least 2 cups (250g) of grated soap; place in either a stainless steel or glass bowl. The general idea is that the soap melts far easier when small, and you achieve a much smoother consistency.
2. Melt the soap. Add the water (or you can choose coconut milk for a smoother consistency of soap) to the milled noodles in the bowl, use just enough liquid to wet the flakes. (If you use too much liquid, you’ll just have to wait longer for the soap to cure — see step 6.)
Some guide to volume of liquid required with our Organic Soap Noodles (Not required with our Rebatch Base (shop link)
Place the bowl over a saucepan of water about a third full to create a double boiler. Over medium-low heat, stir frequently and gently with a wooden spoon so that soap doesn’t stick to the bottom of the bowl and you don’t make suds. Stir until the soap liquefies. (If soap appears to be drying out, add water or milk.) It should appear somewhat lumpy and translucent)
Another way is by using a baking or "oven" bag where you can use the bag as a piping bag to get the soap into the moulds once the melt is finished. As with the double boiler crockpot method, add the grated soap and liquid/milk into a boiling bag. Then close the bag tightly with a twist-tie and put it into a large pot of lightly boiling water.
3. Add other ingredients. Using oven mitts, remove the bag from the boiling water or look inside the double boiler. Check the soap mass. It should have started to soften, and become translucent by now. If it hasn't, just be patient, it will.(approx 30 minutes for 250g soap & added water). You are now ready to make the additions. Be very careful; the soap mass will be very hot!Place the bag onto the counter and open it up. Be very careful of escaping steam. Add the additives, fragrances or colours you want. We suggest no more than 3% fragrance oil in your ReBatch as too much oil can affect the set time and the performance of the soap. Close the bag back up and squish it to mix up all ingredients. Or mix the ingredients in the pot thoughly.
4. Pipe or spoon soap into moulds. You can use either a plastic rectangular container or you can use cake-candy moulds , or any other type of mould you like. You can also use moulds of seasonal shapes, such as Christmas trees or stars, for a festive look. If you have used the oven bag cut a cormer and use it as a piping bag, alternatively spoon the ReBatch mix into your prepared moulds. Tap the moulds gently on the counter to settle the soap and remove any possible air pockets.
5. Cool the soap. Let the soap sit in the moulds for a few minutes and then place in the freezer for up to an hour, to make it easier to remove from the soap.
6. Cure the soap. This process can take up to three weeks dependent upon the amount of liquid added. Place the soaps on a drying rack so that air can get to all sides. Once hardened, the soaps are ready to be wrapped and used or presented as handmade gifts!
For a decorative touch, wrap the bars in plain white tissue paper,parchment or celophane and secure the wrapping with a ribbon or length of yarn, and attach a handmade tag that indicates what’s in the soap.