Tag Archives: saponification

Jun
26

Soap Making Terms


This entry was posted in cold process soap, cold process soap scents, cold process soap vs melt and pour soap, free soap recipes, handcrafted soap, hot vs cold process soap, how to make cold process soap, melt and pour soap, Natures Garden, soap, soap fragrance, soap making problems, Soap making supplies, soap recipe, soap scent, soapmaking, wholesale fragrance oils and tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on by .

Soap Making Terms

If you want to learn about different soaping methods and get help for potential problems, then it helps to know common soap making terms. Whether you are a beginner or experienced, you are likely to come across something new with your batches at least once. So, we are here to help you understand what to do and how to solve any soap-making issues.

Soap Making Terms: How Much Fragrance Oil Can I Add to Soap?

While you should always check the usage rate for each individual fragrance, the maximum that we recommend is 5%. Sometimes you can a scent where the IFRA sheet allows more and you can do more if you’d like. After you know the usage rate, you just need to do some simple multiplication to figure out how much scent you need.

Formula: Weight of Soap x Usage Rate = Weight of Fragrance Oil
Example: 912 grams of soap x 0.05 (which is a 5% usage rate) = 45.6 grams of fragrance

Soap Making Terms: Why Did My Soap Turn Brown?

Often fragrance oils that contains a high amount of Vaniilin will turn soap brown. Also, the color will be a darker brown with scented oils with higher amounts of Vanillin. We can use Vanilla White Color Stabilizer to reduce these effects and still use the scent. Since this ingredient is added to provide a vanilla scent, strong vanilla fragrance oils will almost always turn soap brown without the color stabilizer.

Soap Making Terms: Can I Use Essential Oils in Soap Making?

Yes, essential oils can be used to scent soap. We find that essential oils hold up better in MP soap than in soap made from scratch. This is because the saponification process can cook off the essential oil, which doesn’t have middle notes to anchor the scent. You may have some scent after the soaps cure, but it won’t be as strong as it is in MP soap.

Soap Making Terms: How Much Essential Oil Can I Use in Soap?

This can be different for each essential oil, so you will need to check the IFRA sheet for the usage rate. Then, you can figure out how much you need using the same method as you would for fragrance oils.

Soap Making Terms: How Do You Make Soap White?

You can add titanium dioxide to soaps to make them white. In fact, many of our white soap bases use this ingredient. If you wanted, you could use this ingredient to turn your clear soaps to white.

Soap Making Terms: What is Melt and Pour Soap Making?Soap Making Terms: What is Melt and Pour Soap Making?

Another option for soap making is melt and pour soap. This method starts with a soap base that has already gone through the saponification process. So, you cut need to cut and melt the amount your need before you are ready to add colorants, fragrance, or herbs. Then, you can pour the melted soap into a mold and spray the top with rubbing alcohol. As soon as the soap is hardened, it is ready to use!

Soap Making Terms: How Much Melt and Pour Soap Will I Need for My Mold?

For each ounce by volume in your mold you will need 31 grams of soap. Say the soap mold will hold 16 ounces, you will need 496 grams of soap

Formula: Constant Value for Soap Needed to Fill Mold x Volume of Mold = Weight of Soap
Example:
31 grams per ounce x 16 ounce mold = 196 grams of MP soap

Soap Making Terms: How Long Should Melt and Pour Soap Stay in the Mold?

This can vary based on the size of soap you are creating. Smaller soaps will take less time compared to bigger soaps. Just make sure that they are hardened all the way before you remove them. Also, you should be able to feel that the mold is no longer warm to touch.

Soap Making Terms: How Do I Get My Melt and Pour Soap Out of the Mold?

While you should be able to hold your molds upside down and lightly push, sometimes they get stuck. If you place your soaps in the refrigerator for a short amount of time, this should make it easier for you to remove your mp soap.

Soap Making Terms: How Do I Get Fingerprints Off My Melt and Pour Soap?

Sometimes when you are removing your soaps from the mold, you can transfer a fingerprint. Just use some rubbing alcohol to dampen a cotton swab and  gently swab the fingerprint. It should begin to fade as you do this.

Soap Making Terms: Can Melt and Pour Soap Be Used Right Away?

Of course! The saponification process is already complete before you get your soap base. So, there is no active lye to worry about. This means that you can use your soaps as soon as they harden.

Soap Making Terms: Why Is My Melt and Pour Soap Sweating?

There are a few reasons why your soap would sweat. First, it could be due to adding too much oil. Whether it is fragrance oil or carrier oil, the soap can only hold on to so much before the oil begins to leak out to create beads on the surface. More often, it is due to the soap drawing moisture from the air. Since your soap base uses vegetable glycerin, a humectant, it will draw moisture to it. Although this is great for you skin, it can lead to your soap sweating . However, you can prevent the latter by wrapping your soap as soon as it comes out of the mold. This way it can’t pull moisture from the air.

 

Soap Making Terms: What is Hot Process Soap Making?Soap Making Terms: What is Hot Process Soap Making?

Another way to make soap from scratch is hot process soap. This process is very similar to cold process soapmaking. However, in this method you will have a heat source to speed up the saponification process. You can use a crock pot or stove top to heat your soap mixture. After, you can technically use the bars immediately. However, letting them cure a week will provide you with harder, milder bars.

Soap Making Terms: Does Natures Garden Offer Any Hot Process Soap Recipes with Shea Butter?

Yes, we have a few! For example, we have our Manly Soap Recipe, the Beard Soap Recipe, and more that you can find under the Hot Process Soap Recipes page!

Soap Making Terms: How Long Do You Have to Wait to Use Hot Process Soap?

Yes. Although you don’t have to wait as long for your soaps to cure, there is still some lye left that needs to react. Typically, you will need to wait 1-2 week(s) before using your hp soap.

Soap Making Terms: What Does Rebatch Mean?

If you want to redo a soap batch or add more ingredients, then this is a great idea for you! It is common to rebatch to correct issues like seizing or forgotten ingredients. Also, this can be done to add ingredients that wouldn’t react well during the saponification process, like natural exfoliates or essential oils. First, take the soaps that you aren’t necessarily pleased with and grate them into pieces. Place these pieces in a crock pot and melt them with milk, water, or another liquid to prevent scotching. Also, add any additional oils that you want in these soaps. Allow you batch to reheat for one hour at which point it will by thick. After, add the color, scent, and herbs before scooping this soap into a mold.

Soap Making Terms: What is Cold Process Soap Making?Soap Making Terms: What is Cold Process Soap Making?

This process is one of a few that are refereed to as making soap from scratch because in uses water, lye, and oils to create bars of soap. Another key characteristic of this method is that you don’t need outside heat, as the lye provide enough heat for saponification. Once trace occurs, you are able to add colorants, scented oils, and herbs can be added at this point. After 24 hours, you can remove the soap from the mold and cut. However, you must let your soap cure for a period of 4-6 weeks.

Soap Making Terms: What is Lye in Soap Making?

Lye is a caustic base that is a key component for soap, as it drives the saponification process. It is sometimes referred to as sodium hydroxide for bar soaps and potassium hydroxide for liquid soaps.

Soap Making Terms: What Does Saponification Mean?

This is the process of lye reacting with the oils/fats/butters to produce soap. Saponification will produce both the soap and the glycerin in the soap.

Soap Making Terms: What Does Cure Time Mean?

Cure time is the period where the soap finishes the soaponification process until there is no more active lye present in the bars.

Soap Making Terms: What Does the Term Trace Mean in Soap Making?

In soaping, trace is when the lye water and the oils/butters have been fully combined. You will know that you’ve hit trace because the batter will thicken to a pudding-like consistency. Also, you can check to see whether you are at trace by using a spatula to “trace” a line of soap in the batter. You will notice that the line will not immediately disappear and you can see a trace of the soap you drizzled in.

Soap Making Terms: What Does Light Trace Mean in Soap Making?

Light trace is the point right before your soap comes to trace. You will begin to see a trace, but it won’t stay for more than a few seconds. So, the batter is about to hit trace where it will be thick enough to see the soap for a bit longer.

Soap Making Terms: How Long Does It Take for Soap Batter to Get to Trace?

The time is takes to get to trace will vary between batches for a number of reasons. The ingredients in a recipe can lead to different times. Also, fragrance oils and some soap additives can accelerate or slow trace in your batch.

Soap Making Terms: What Does Seize Mean in Soap Making?

If your soap seizes, then it means that your soap has gone through saponification enough that the batter is beginning to turn from liquid to solid. While this isn’t bad on its own, it makes it impossible to pour soap that is still in the bowl. This hardening soap that hasn’t yet made it to the mold will be too thick to mix and, at best, will be chunky in the mold.

Soap Making Terms: Why Do I Have Lye Pockets in My Cold Process Soap?

If you use too much lye in your soap recipe, then you can
Lye pockets can form in cold process soap most often when too much lye is used. However, it could also be a recipe that wasn’t properly formulated, an oil was left out, the soap seized, or even when the lye solution was not fully mixed. If the lye was not completely saponified you can always rebatch the soap and hot process the soap adding additional oil. Also, it is possible that it could be used in recipes such as laundry soaps that can utilize soap with a higher pH level.

Soap Making Terms: Can I Change the Soap Making Recipes?

Unlike many other bath and body recipes, you can’t simply swap out oils in the Natures Garden formulated recipe. Each oil has a certain saponification value that determines how much lye it will react with. So, switching an oil could result in your batch being lye heavy. Even if you wait longer to cure, there won’t be enough oils to react with the lye and the bars will irritate the skin or even cause burning. Instead, use SoapCalc to determine what you would have to change to get the recipe that you want!

Soap Making Terms: Reach Out to UsSoap Making Terms: Reach Out to Us

If you have any other questions or concerns about soapmaking, then please reach out to us! One easy way to ask us something is on social media. You can find us on Facebook, Twitter, and Instagram. Have fun soaping!

 

Jul
08

What is Trace in Soap Making?


This entry was posted in bath and body, bath products, cold process soap, Fragrance Oils, Natures Garden, Natures Garden Fragrance Oils, Soap making supplies, Uncategorized and tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on by .

What is trace in soap makingWhat is Trace in Soap Making?

What is trace? Baby, don’t blend me; don’t stir me, just pour. Trace is when you’ve reached emulsion- your oils are blended with your lye mixture and are no longer capable of separating. How can you tell when your mixture is at trace? The easiest way is to use your stirring utensil: hold it a few inches above your mixing container and move it back and forth. If the soap batter dripping off the stirring utensil leaves little lines that sit on top of the mixture in the bowl- that’s trace. It can be difficult to capture in photographs, but you’ll know it when you see it in motion.

heavy traceSo I reach trace and that’s it? Well, yes and no. There are different degrees of trace, but the important thing to remember is that once a mixture has reached trace- it’s only going to continue to solidify from there. Light trace is considered the bare minimum. Light trace is helpful when you’re looking to make swirls or other designs that require easily pourable, almost-liquid soap. Moderate trace is in the goopmiddle and means you’re ready to pour your soap into the mold. Heavy trace is when your soap gets thick. The picture above shows heavy trace. A soap batter at heavy trace is resistant to change shape and almost impossible to pour into a mold. Heavy trace may result in the need to scoop your soap into the mold, seen in the photo on the left. Not a pretty sight. Work quickly to ensure the soap does not set before you are ready.

What Causes Different Levels of Trace?

Trace can be affected both by your ingredients and your blending method.

Ingredients:

  • ‘Hard’ oils, including palm oil and coconut oil, and butters will reach trace much faster. Using softer oils such as olive oil or canola will decrease the speed of trace, but your end product soap will be much softer. Increasing the amount of oil to superfat your recipe will also slow down trace. (Be careful not to add too much or you’ll have an excess of unreacted oils.)
  • In addition, fragrance oils can accelerate trace. (Check out our CP Soap Testing results to see how our fragrance oils perform in the CP soaping process.)
  • Inversely, the more water you use, the slower your soap will reach trace. A water discount (using less water than the recipe called for) will accelerate trace and is recommended for only advanced soapers when they see fit.

Blending:

  • The speed at which you blend can accelerate trace. Using a stick blender as opposed to stirring manually with a spatula will increase the speed of the reaction and trace will be reached faster. If you suspect that the mixture will accelerate, stir it manually to slow the rate of trace.
  • Furthermore, the temperature at which you blend your ingredients will affect trace. Higher temperatures accelerate trace. If you wish to slow down trace, let your lye mixture cool down to about 100 degrees Fahrenheit before you add it to your oils.
  • The order also matters. If the fragrance oil you’re using is known to have a tendency to accelerate trace, be sure to add it last, after you’ve made your soap mixture and added any colorant, and be ready to move.

False Trace

All this talk about trace and the need to rush your soap process may have you running around like a chicken with its head cut off- but BEWARE FALSE TRACE. False trace usually occurs when oils in your mixture begin to cool down and solidify without going through emulsion or saponification. So, much like Goldilocks, you don’t want your mixture to be too hot or too cold, but juuuuust right.

Ahhh!

I know it seems like a lot- but if you pay attention to the factors listed here- you should be alright. Remember to have all of your ingredients ready before you start soaping (always, but especially) in case of any unexpected trace acceleration. You can do this, I promise. And if something goes wrong, you can always melt down your soap and try again. Thanks for reading and happy soaping!

Jul
02

Coconut Oil 76 in CP Soap


This entry was posted in bath and body, bath products, cold process soap, Natures Garden, Natures Garden Fragrance Oils, Soap making supplies, Uncategorized and tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on by .

Coconut-Oil-76-in-CP-SoapCoconut Oil 76 in CP Soap

You’ll go coco-nuts for coconut oil 76 in CP soap. What does the ’76’ mean? It simply denotes that this type of coconut oil has a melting point of 76 degrees Fahrenheit. Coconut oil has many beneficial properties for use in all sorts of products–it’s even edible!!–but for our purposes, we’re going to discuss coconut oil 76 in CP soap. (Please do NOT attempt to eat the soap.)

Coco Clean

Our cold process soap testing recipe features coconut oil as the second most abundant ingredient (by weight) after water. Rightfully so, for you see, coconut oil is comprised primarily of lauric and myristic fatty acids which are characterized in soap-making by providing cleansing properties, a bubbly lather, and hardness. Coco-o is a surfactant, meaning it reduces the surface tension of a liquid when it is dissolved, allowing the dirt and impurities to be rinsed off of the skin.

Coco Cream

In addition, the high content of saturated fat serves to give coconut oil a higher SAP value (the number of milligrams of lye that is needed to completely saponify, or turn into soap, one gram of a specific oil, butter, or fat. — Lye, while generally thought of as a bad guy, is a necessary evil for the saponification process. Always remember to follow safety procedures when handling lye. [Add lye to water, the mixture will get hotter; add water to lye, you’ll probably die]). Remember that rhyme to ensure safety.  While you will likely NOT actually DIE, you can certainly get hurt from the lye volcano you will create if you add water to lye.  SO… Don’t ever do that!  Always add your lye to your water.  The high SAP value of coco-o helps to superfat the soap (the amount of lye used is less than the given SAP value), giving it a nice, creamy texture and more lather ability. You can thank coconut oil for making your homemade CP soap clean and bubbly.

Coco – What the heck does that mean?

Furthermore, coconut oil serves as an emulsion stabilizer. What the heck does that mean? You may already know, but I just learned about this today, so I’m going to recap for myself and the benefit of anyone out there who’s not entirely sure. An emulsion is a mixture of two things that don’t really want to go together– for instance, oil and water. Water is the number one ingredient (by weight) in our CP soaps, and just about everything else is some type of oil (apricot kernel oil, castor oil, sunflower oil, palm oil, fragrance oil, and- of course- coconut oil 76). An emulsion stabilizer helps to keep this mixture from separating. This means, not only will it help hold your soap together, it will also help hold the fragrance. (Don’t worry, the coconut oil itself has been refined so it is odorless. Unless you ARE looking for a coconut fragrance in your soap. If so, we’ve got ten coconutrelated scents you may enjoy using!)

Coco No-no

Oh, wow, you’re thinking. Coconut oil 76 in CP soap is so great, I want to use as much of it as possible! And of course you do, but how much is too much?  A typical soap recipe calls for 20-30% coconut oil. It’s important not to use more than 30% coconut oil. Why? Is it possible to be TOO clean? The excess coconut oil 76 in CP soap will interact with the natural oils on your skin and dry it right out. But if you use the appropriate amount of coconut oil, it works in the soap to help clean skin and even reduce inflammation.

Cococonclusion

Coconut oil 76 in CP soap is awesome as long as you’re careful not to use too much in your recipe. So go ahead– what are you waiting for? Follow the links above to purchase coconut oil 76 and other ingredients for our CP soap testing recipe or one of our other fun CP soap recipes. Browse our wide array of fragrance oils to find a scent that you love. Thanks for reading and happy soaping!

Mar
18

Color Morphing in Soap


This entry was posted in bath and body, bath products, cold process soap colorant, Natures Garden, soap, Soap making supplies and tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on by .

color morphing in soapColor Morphing in Soap

For any new soap makers out there like myself, do you have specific questions? For example, do you know which kind of soap colorant to use when you are coloring cold process soap? Or have you ever wondered about color morphing in soap? Here at Nature’s Garden, we offer two different kinds of colorants for soap: one being a our FD&C Da Bomb Soap Dyes, and one being our FUN Soap Colorants which are pigments dispersed in vegetable glycerin. The use of each kind of colorant is based on pH levels and the actual saponification process. The saponification process is considered the creation of soap by combining oils/butters and water with lye (which has a high ph). Throughout this process as the soap cures, the pH level (alkalinity) become lower.  It is important to understand that pigments tend to withstand higher ph levels better than dyes (especially when dealing with the color blue).  In our experiment, we show how blue dye and blue pigment perform in both melt and pour soap (soap that has already been saponified) and cold process soap (soap that is made from scratch and will undergo the saponification process).

In melt and pour soap, because it is technically already soap, it has already gone through the saponification process;  so the alkalinity is lower. The dyes, our Da Bomb colorants, do not cause any color morphing problems when used in melt and pour soap. They will color beautifully, as well as our pigments, or FUN Soap Colorants. In the picture below, this light blue colored bundt soap is made with melt and pour soap, as well as our Blue Da Bomb colorant. You can see how nice and pretty this blue coloring is. When melt and pour soap is colored with blue FD&C dye, it will produce a beautiful blue colored soap since the dye never has to encounter a high ph.

color morphing in soap

color morphing in soap

However, when different colorants are used in cold process soap, as seen below, the outcome is very different. Because cold process is made completely from scratch, it must undergo the entire saponification process.  This means that the pH levels are much higher in cold process soap. In the pictures below, the darker blue soap was made using our pigmented, Ultramarine Blue FUN Soap Colorant. The purple soap, (started as gray and turned to reddish-pink-purple as it sat) was created using our Da Bomb blue dye. (We have used our Shea Butter Cold Process Soap recipe for this part of our experiment).  It is evident that blue FD&C dye (our Da Bomb blue dye)  will morph in color when exposed to a high ph.

color morphing in soap

color morphing in soap

color morphing in soap

In conclusion:  When desiring a nice blue color for your cold process soap, it is wise to use blue pigments instead of blue FD&C dyes.  While the blue FD&C dyes work wonderfully in melt and pour soap, they will indeed morph in color when making cold process soap.

Please contact us here at Nature’s Garden if you have any questions, comments, or concerns at all! We are here to help you and to make sure you succeed at all of your creations! Make sure to check out all of our amazing free recipes and classes as well, especially all of our soaping classes! And keep watching for more Enlightened by Layla!

enlightened-by-layla (1)

Apr
22

Rebatching Soap


This entry was posted in bath and body, bath and body fragrances, bath products, cold process soap, cold process soap colorant, cold process soap scents, Fragrance Oils, handmade soap, homemade, Natures Garden, soap ingredients, soap making recipes, Soap making supplies, soap mold and tagged , , , , , , , , , , , , , , , , , , , , , on by .

rebatching soap Whether you view rebatching as an art, a doorway for the addition of gentle ingredients, or a second chance for your soap, this method of soap making offers opportunity.

The term rebatching for soap simply means remaking soap.  This method would be very similar to melt and pour soap in that you are melting down soap that has already gone through the saponification process.  Rebatching is more intricate than melt and pour soap though.  Rebatching involves cold processed or hot processed soap bars that are melted down for specific reasons.

A common technique used in soap making, rebatching allows many soap making handcrafters the chance to rework their soap recipes, introduce delicate scents and herbs, as well as add ingredients or colors they may have missed the opportunity to add the first time.

Since rebatched soap has already gone through the saponification process, the rebatching steps do not involve lye.  This is why rebatching allows the opportunity to add those delicate soaping ingredients; without fear.  With the rebatching method, these ingredients; which normally would not survive the saponification process, now have the chance to add wonderful benefits to your finished bars of soap.

Although time consuming, the rebatch process is fairly easy to do.  To put it briefly, the rebatching process is finely grating the soap, then heating (sometimes with the addition of a liquid like water to help prevent burning).  There are a few different ways to introduce heat to the shredded soap.  These ways would include:  double boiler, microwave, and crock pot.  But, please advise: you must monitor the soap while it is heating because you never want to scorch the soap.  This may be slightly more difficult using the microwave approach.

Now, as the soap is heated and starts to liquefy; it will have a very thick gel like density.  Once the soap hits this consistency, any additives or scents are added and stirred in.  Once the soap is stirred well, it is then scooped into a mold, left to harden, and finally cut into slices.

So, now that you have an understanding as to what the method of rebatching is, we will shortly post a blog as to the various reasons to rebatch.  This post will also cover the benefits as well as the drawbacks of rebatching your soap.

Apr
18

Why Rebatch


This entry was posted in bath and body, bath products, body safe fragrance oils, cold process soap, cold process soap colorant, cold process soap scents, essential oils, Fragrance Oils, handmade soap, homemade soap, natural colorants, Natures Garden, soap ingredients, Soap making supplies and tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on by .

rebatch soapRebatching your soap can literally be a “saving redo” for your soap recipe.

Sometimes your homemade soap bars are cracked, brittle, or just not performing like what you were hoping for. 

These are all perfect examples as to why you would rebatch your recipe.  But, it just doesn’t stop there. 

Soapers rebatch a soap recipe for a variety of reasons.  Below is a list of the benefits and key points you should know about rebatching a soap recipe.  Rebatching soap is essentially making the soap twice.  The first time you are completing the saponification process.  (Or, you may be using soap that has already been through the saponification process.)  Then, the second time you grate down the soap and melt it (for the reason you are rebatching). 

Benefits of a Rebatch
Rebatching a soap recipe for the addition of heat sensitive ingredients: 

Sometimes with homemade soap crafting, there are certain fragrances or essential oils that you really want to scent your soap bars; but worry that the scents cannot handle the high heat due to the saponification process.  Many times with low flash point fragrances or essential oils, there is scent burn off.  What results in your finished bars is soap that has little or no scent.  Rebatching soap will not only safely allow you to add these heat sensitive scents, but allow them to stay true to their scent (less burn off). 

Also, some fragrance oils may cause cold process soap to seize (turning your soap into a solid mass with no fluidity).  If you have your heart set on using one of these fragrances in your soap recipe, it can be done through the process of rebatching; without seizing your batch.  Usually fragrance oils that seize  your soap contain DPG.  None of the fragrance oils we carry at Natures Garden contain DPG. 

When it comes to coloring for cold process soap, it is very important to select ones that do not morph.  Through the process of rebatching, you do not need to worry about pH sensitive colorants.  And, sometimes this is just the answer to achieve that certain color.  With rebatch soap, the soap base that you are using has already completed the saponification process; therefore, the colorants that normally would discolor will not.   This is true for herbs that are used as natural soap colorants as well.  Although it should be stated that some herbs naturally discolor due to oxidation. 

Herbs not only offer color, but also wonderful and various benefits to your finished bars of soap.  The only problem is they can directly affect your soaping procedure.  Many herbs can speed up trace.  Even more so, some herbs cannot survive the saponification process and will discolor as a result.  With rebatching, this is not as big of an issue.  Herbs like lavender flowers, for example, can be added without worrying that those beautiful flowers will turn brown. 

Rebatch Opportunity
Rebatching allows for perfection:

Rebatching is also a wonderful method to use to correct a soap recipe.  Things can get a little chaotic when soaping, and it could be possible that you overlooked adding one of your soaping ingredients and did not realize it until after the soap was molded.  This resulted in your finished bars being too lye heavy.  A rebatch allows you the perfect opportunity to add that missing ingredient and balance out your soap.  This opportunity also allows for superfatting a recipe after saponification; or correcting soap bars that are too soft (made with too many fats or soft oils).

It is possible too that while making soap, your batter becomes too thick too quick for the addition of color or scent.  With rebatch, the soap can be scented and colored like you never missed a beat. 

Rebatch can also help correct a false trace recipe.
 
Rebatch, a Second Chance for Soaps
Sometimes, as a soaper, you will have pounds of soap scraps that you have on hand.  Rebatching the soap lets you make loaves (and bars) of them once more.  And will clear out all of that soaping space. 

Points to Know about Rebatch
Some soapers love to rebatch soap, others rebatch only when necessary, and some soapers just do not like to rebatch.  What ever your stance is on rebatch, it is a method that allows for many otherwise missed opportunities.   Here are some key points to know about rebatch. 

When making soap that is a rebatch, it will never completely liquefy.  Even after spending hours in the crock pot, or on the stove top (with the double boiler method), the best you will ever achieve is more of a thick gel like state.  Sometimes the soap may even be globby like.  This does not affect the soap being soap, but it will affect the finished look of your bars. 

When it comes to molding your rebatch soap, it is highly likely to get trapped air bubbles.  This is just the nature of the thick gel like globby beast.  It is extremely important to tap your mold as your fill it to prevent these pesky little buggers from being a problem in your finished soap bars.  You may also notice that it may be slightly more difficult to mold your soap while in this state.  This will be especially true if you are used to pouring it (like cold process soap batter).  With rebatch soap, you will need a ladle and scoop the rebatch soap into your mold. 

For the finished bars of rebatch soap, they will look very similar to hot process soap bars.  They have a very rustic look to them, and will not have the traditional smooth and creamy look that cold process has. 

On a final note, rebatching soap is truly a labor of love.  There will be lots of TLC (because of the time put in) and additional work to do this method.  But, if you are willing to put in the extra effort in (grating the soap), you will be able to rebatch your soap and have the end results that you are looking to achieve.