#### ngian

##### Well-Known Member

Hello everyone

On my latest soap that I made I wanted to use new methods in order to make it and that involves making all the calculations with a pencil and a paper, making a dual alkali soap, and using a full water replacement with vinegar. A while ago topofmurrayhill has posted the "manual" way of calculating ingredients for a recipe without the need of an electronic soap recipe calculator and also how to calculate the excess lye needed for the vinegar in a recipe. Also DeeAnna has shown us how to correct the amount of alkalies really needed in order to make an actual lye discount, eliminating the hidden one found inside the alkali.

I would like to write all these steps once more in one place along with dual alkali calculations that I did on my latest recipe. It is really easy to do them by hand and I feel that someone gains even more control in the entire soaping process.

The only thing we need to know is the SAP value of each oil that our recipe will have. My recipe had

75% Olive Oil (with very low acidity) (600gr)

20% Palm oil and (160gr)

5% Castor oil (40gr)

This recipe could also be named as the no coconut oil soap as I was trying to have bubbles from the addition of the 10% KOH alkali.

So let's start:

The first step to do is to find the quantities of the alkalies needed to saponify our oils based on their SAP values for both NaOH and KOH:

Grams alkali needed for its saponification:

Grams alkali needed for its saponification:

Grams alkali needed for its saponification:

So if we sum all grams of soda (NaOH) and all the grams of potash (KOH) will have the total weight of the respective alkalies needed to saponify the oils:

Saponification of all oils only with

Saponification of all oil only with

These weights however are for 100% purity, which is not so in reality. According to the Certification of Analysis documents that the supplier gave me, the NaOH I have in my hands is

Corrected alkali weight = amount of alkali we calculated above x (100% purity / purity of the alkali that we have in our hands)

NaOH = 108,84 x (100/

KOH = 153,04 x (100/

So these weights are what we need to make a soap with an almost real 0% lye discount (I'm writing "almost" as I don't know the real SAP number of the oils I have in hand).

The next step is to calculate the weights of each alkali we will use depending on their percentage use in the recipe. In this I decided to use

(If we wanted to use it 95% NaOH in the recipe, we would multiply by 0.95).

(For example if we wanted to use 5% KOH in the recipe, we would multiply by 0.05).

The next step is to calculate the weights of alkali we found above with 3% discount (or as much discount you usually do in your soaps) in both NaOH & KOH:

NaOH discount of 3%, 100g x

KOH discount of 3%: 17,9gr x

(For example if we wanted to make NaOH / KOH discount of 6% in the recipe then you multiply by 0.94)

After calculating all the alkalies needed for our recipe then we can calculate the water needed based on them. The lye concentration that I will use will be

Water needed for NaOH: 97 x

Water needed for KOH: 17,3 x

So we will need a total of 165 + 30 =

But as I said initially, I will use vinegar instead of water in the recipe, to take advantage of the acetic acid that will offer hardness similar to salt. And thus we should still make one more correction in the amount of the alkalies needed so as for them to react with acetic acid without raising further the recipe's lye discount:

So if you still read me without changing the page in order to read something less boring, we're going to see how to calculate NaOH & KOH we will need to keep the original alkali 3% discount to the recipe.

The vinegar that we have in Greek market is 6% acidity (it is written on its label) and it means that 6% of its weight is acetic acid. The alkalies that are needed to fully react with 1gr of acetic acid is

Acetic acid present in vinegar for NaOH: 165gr x

Additional NaOH needed for the acetic acid: 10 x

Acetic acid present in vinegar for KOH: 30g x

Additional KOH needed for the acetic acid: 1,8 x

Corrected NaOH because of vinegar: 97 + 6.6 =

Corrected KOH because of vinegar: 17.3 + 1.6 =

Thus, after

Olive oil:

Palm oil:

Castor oil:

NaOH:

KOH:

The dissolution of the two alkalies can be done in the same vessel with 195gr of vinegar for simplicity. You can follow any steps that you might need for your recipe and any of them that you feel comfortable with (eg. step 2)

If you managed to read me until here, congratulations!

I also used 3% of French Green Clay and Masticha/Sandalwood EOs. In my soap I forgot to calculate the 6) step and as a result I made the soap with almost 10% alkalies discount. The soap seems perfectly hard (I think that acetic acid makes a "better" hardness compared to sodium chloride, along with 37% lye concentration), it is a bit oily in its surface, and as I was cutting it 9 hours after I mold it and CPOP it for 1 hour, it was really hard to cut.

My next project will be to make it once more but with the calculation of the 6) step along with changing the ratio to 85% NaOH and 15% KOH. Vinegar and water discount is something that I like lately in soaps.

On my latest soap that I made I wanted to use new methods in order to make it and that involves making all the calculations with a pencil and a paper, making a dual alkali soap, and using a full water replacement with vinegar. A while ago topofmurrayhill has posted the "manual" way of calculating ingredients for a recipe without the need of an electronic soap recipe calculator and also how to calculate the excess lye needed for the vinegar in a recipe. Also DeeAnna has shown us how to correct the amount of alkalies really needed in order to make an actual lye discount, eliminating the hidden one found inside the alkali.

I would like to write all these steps once more in one place along with dual alkali calculations that I did on my latest recipe. It is really easy to do them by hand and I feel that someone gains even more control in the entire soaping process.

The only thing we need to know is the SAP value of each oil that our recipe will have. My recipe had

75% Olive Oil (with very low acidity) (600gr)

20% Palm oil and (160gr)

5% Castor oil (40gr)

This recipe could also be named as the no coconut oil soap as I was trying to have bubbles from the addition of the 10% KOH alkali.

So let's start:

**1) Calculation of the saponification**The first step to do is to find the quantities of the alkalies needed to saponify our oils based on their SAP values for both NaOH and KOH:

**Olive oil: 600 g**(SAP - NaOH: 0.135 | KOH: 0.19)Grams alkali needed for its saponification:

**600**x 0,135 = 81gr NaOH**600**x 0,19 = 114gr KOH**Palm oil: 160 g**(SAP - NaOH: 0.142 | KOH: 0,199)Grams alkali needed for its saponification:

**160**x 0,142 = 22,72gr NaOH**160**x 0,199 = 31,84gr KOH**Castor oil: 40 g**(SAP - NaOH: 0.128 | KOH: 0.18)Grams alkali needed for its saponification:

**40**x 0,128 = 5,12gr NaOH**40**x 0,18 = 7,2gr KOHSo if we sum all grams of soda (NaOH) and all the grams of potash (KOH) will have the total weight of the respective alkalies needed to saponify the oils:

Saponification of all oils only with

**NaOH**:**108,84gr**Saponification of all oil only with

**KOH**:**153,04gr**These weights however are for 100% purity, which is not so in reality. According to the Certification of Analysis documents that the supplier gave me, the NaOH I have in my hands is

**98%**pure and the KOH is**85%**pure, if I store them airtight after opening them and I no further decrease their purity with their exposure to the atmosphere. So the correction of purity is the next step:**2) Correction of the alkali weight needed based on their actual purity**Corrected alkali weight = amount of alkali we calculated above x (100% purity / purity of the alkali that we have in our hands)

NaOH = 108,84 x (100/

**98**) => 108,84 x 1,02 => 111grKOH = 153,04 x (100/

**85**) => 153,04 x 1,17 => 179grSo these weights are what we need to make a soap with an almost real 0% lye discount (I'm writing "almost" as I don't know the real SAP number of the oils I have in hand).

**3) Ratio of each alkali in the recipe**The next step is to calculate the weights of each alkali we will use depending on their percentage use in the recipe. In this I decided to use

**90% NaOH**and**10% KOH**, so we will do the following multiplications based on the latest grams of alkalies we found above:**Using NaOH 90%**: 111gr x**0,90**= 100g(If we wanted to use it 95% NaOH in the recipe, we would multiply by 0.95).

**Using 10% KOH**: 179gr x**0,10**= 17,9gr(For example if we wanted to use 5% KOH in the recipe, we would multiply by 0.05).

**4) Lye discount by 3%**The next step is to calculate the weights of alkali we found above with 3% discount (or as much discount you usually do in your soaps) in both NaOH & KOH:

NaOH discount of 3%, 100g x

**0,97**= 97grKOH discount of 3%: 17,9gr x

**0,97**= 17,3gr(For example if we wanted to make NaOH / KOH discount of 6% in the recipe then you multiply by 0.94)

**5) Calculation of water**After calculating all the alkalies needed for our recipe then we can calculate the water needed based on them. The lye concentration that I will use will be

**1,7: 1**(**37%**lye concentration) which practically means that the amount of water is the weight of the alkali multiplied by 1,7. So according to the latest amounts we got at step 4 we have:Water needed for NaOH: 97 x

**1,7**= 165grWater needed for KOH: 17,3 x

**1,7**= 30grSo we will need a total of 165 + 30 =

**195gr**distilled water to dissolve the alkalies.But as I said initially, I will use vinegar instead of water in the recipe, to take advantage of the acetic acid that will offer hardness similar to salt. And thus we should still make one more correction in the amount of the alkalies needed so as for them to react with acetic acid without raising further the recipe's lye discount:

**6) Alkalies correction due to vinegar**So if you still read me without changing the page in order to read something less boring, we're going to see how to calculate NaOH & KOH we will need to keep the original alkali 3% discount to the recipe.

The vinegar that we have in Greek market is 6% acidity (it is written on its label) and it means that 6% of its weight is acetic acid. The alkalies that are needed to fully react with 1gr of acetic acid is

**0,66gr NaOH**and**0,92gr KOH**respectively. So for the "water" we calculated above we must do the following:Acetic acid present in vinegar for NaOH: 165gr x

**0,06**(6%) = 10gAdditional NaOH needed for the acetic acid: 10 x

**0,66**= 6.6 g NaOHAcetic acid present in vinegar for KOH: 30g x

**0,06**(6%) = 1.8 gAdditional KOH needed for the acetic acid: 1,8 x

**0,92**= 1.6 g KOHCorrected NaOH because of vinegar: 97 + 6.6 =

**103,6gr**Corrected KOH because of vinegar: 17.3 + 1.6 =

**18,9gr**Thus, after

**all**of the six steps above we have:Olive oil:

**600gr**Palm oil:

**160gr**Castor oil:

**40gr**NaOH:

**103,6gr**in**165gr**of vinegarKOH:

**18,9gr**in**30gr**of vinegarThe dissolution of the two alkalies can be done in the same vessel with 195gr of vinegar for simplicity. You can follow any steps that you might need for your recipe and any of them that you feel comfortable with (eg. step 2)

If you managed to read me until here, congratulations!

I also used 3% of French Green Clay and Masticha/Sandalwood EOs. In my soap I forgot to calculate the 6) step and as a result I made the soap with almost 10% alkalies discount. The soap seems perfectly hard (I think that acetic acid makes a "better" hardness compared to sodium chloride, along with 37% lye concentration), it is a bit oily in its surface, and as I was cutting it 9 hours after I mold it and CPOP it for 1 hour, it was really hard to cut.

My next project will be to make it once more but with the calculation of the 6) step along with changing the ratio to 85% NaOH and 15% KOH. Vinegar and water discount is something that I like lately in soaps.

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