The Pros, Cons & Method For Rebatching Soap

“Also known as hand-milling soap, you can save botched batches that you would normally have to be thrown out.”

rebatching homemade soap

Rebatching soap, also known as hand-milling soap, is basically the procedure of melting down premade cold process soap. Rebatching is one of those procedures you will love or hate, so let’s take a look at the good points first.

rebatching homemade soap

Positives of Rebatching Soap

  • This process will allow you to add in any extra delicate additives such as herbs, essential oils and other various ingredients that could easily be ruined by alkalinity in the cold soap process.
  • You can also save botched batches that you would normally have to be thrown out. Simply re-melt and add any oils or ingredients you may have forgotten, or just miss-weighed or miss-calculated (have you ever had that sinking feeling when you’ve just realised you’ve forgotten to add in a particular colouring or additive, after you’ve poured them into molds? and it’s all too late, well guess what, You’re not alone!)
  • Rebatching soap also allows you to take one large batch of plain, uncolored or perfumed soap and divide it into an assortment of individual recipes.

Negatives in Rebatching Soap

  • Rebatching soap is quite a lengthy process (it could take 2 to 3 hours just to melt the soap).
  • Rebatched soap doesn’t always have the nice smooth look and feel of freshly made cold process or melt and pour soap. And often has to be trimmed and shaped once its hardened.

Rebatching Process

So having noted the pros and cons of rebatching soap lets get to the process.

For best results, try rebatching soap when it’s still fresh (about 2 to 10 days would be considered fresh). The fresher the soap the more water it will still contain making it much easier to work with.

If your soap is older than 10 days don’t worry, you can still rebatch it but you will need to replace the moisture the soap will have lost. For a vegetable based soap its best to add milk to it when melting, I’ve used cows, goats and buttermilk and all have worked well. For a tallow base soap use distilled water.

What you will need

  • Cold process soap
  • Liquid (distilled water or cold milk) approximately 9 oz per lb of soap; if your soap is very fresh then you’ll need less or even none
  • Large hole grater
  • Double boiler, an electric oven, or a crockpot

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  1. Start by shredding or grating the soap as finely as possible then place it in to a crock pot, ovenproof bowl, or the top half of a double boiler. Add the appropriate amount of liquid remembering to use milk for the vegetable based soap and distilled for the tallow based soap. Give it a good stir until all your soap is completely coated in the liquid, and then leave it to sit and absorb some of the liquid for 2 or 3 hours before melting.
    rebatching soap
  2. Don’t forget that if your soap is still nice and fresh, you shouldn’t need to use any liquids, but if your soap is looking rather dry it’s a good idea to add a little, this will create a layer which will stop the bottom from burning.
  3. If you are using a crock pot turn it on to the lowest setting. Your oven will need to be set at 145F to 150F and the double boiler needs to be kept at a steady boil.
  4. Stir the soap well and then cover it, if your ovenproof bowl doesn’t have a lid cover it with foil. If you are using a double boiler, keep your eye on it giving it a quick check every 10 minutes or so. If you’re using a crock pot or an electric oven, then you will only have to check on it every half an hour or so. Try not to stir the mix whilst it’s melting, just give the sides a scrape down each time you check on it.
    melting soap for rebatching
  5. After 2 to 3 checks, if your soap is still looking fairly solid, and a little dry, add some extra liquid and give it a gentle stir. As the soap becomes smooth (this stage will take a while, up to an hour or more, so try to be patient) don’t add any more liquid at this point but if you are using the double boiler method, keep your eye on it to insure that the bottom is not burning. If you do see your soap starting to burn, then to reduce the temperature by adding a little cold water to the bottom of the boiler to cool it down.
  6. After a while (anywhere between 1 to 2 hours), the soap mix will get to a point where it isn’t going to get any smoother, and it’s consistency will no longer change. This is a good time to add any additives to your soap. Stir in the additives and continue heating and thoroughly stiring every now and then to insure it doesn’t burn. The soap doesn’t always melt to a total liquid so if the texture doesn’t change for a long time, then it’s not going to. Remove the soap from the heat and let it cool for a little while.
  7. Prepare a mold by rubbing it with a little petroleum jelly (I personally prefer to use those flexi silicone muffin trays, mainly because you can easily pop the finished soap out of them without needing to grease them.)
  8. Once the soap has cooled enough, transfer it to a mold by pouring, spooning or pushing depending on how thick the soap mix is. Alternatively you could whip the soap up using an egg beater to produce floating soaps, before carefully spooning into the mold.
  9. Leave the soap to harden (about 24 hours) then remove it from the mold. Trim or shape the soap if needed and allow to dry out (cure) for 3 weeks to make the soap nice and mild before using.

Have you rebatched soap before? What tips can you share with me?

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Angela Wills

Hi, I'm Angela, and I make most of the homemade things here at Savvy Homemade. I’m fearlessly dedicated to creating tried, tested recipes & products that will work for everyone. I'm an experienced soap maker, skincare formulator, author, busy Mom of 3, and recently a Grandma! Welcome to SavvyHomemade, it's my true passion.

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Discussion (23 Comments)

  1. Hello Angela,
    I made my soap about two weeks ago but every time I try to test it I discover it doesn’t foam. What am I going to do now. I used the lye calculator to get the right amount of lye and water.

    • This is very unusual. It doesn’t lather at all? Sometimes, if you have hard water, soap doesn’t lather very well at all. If you have some spring water in a bottle hanging around, try testing with that instead.


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