Citirc acid calculator

[soapman5]

Hello, I was using soapmakingfriend lye/soap calc to calculate the total amount of NaOH when including citric acid, but when I compared it to soapcalc + calculating the added amount of NaOH manually, i get different numbers. The batch is 250 grams of oils and the amount of CA is 1.5 %, SF is at 3 %, lye conc is 33 %.

The formula for manually adding CA is (Citric acid weight, grams) X 6.24 / 10.

- So on soapmakingfriend lye calc I get 34.86 g of NaOH without adding CA in the calc and 36.58 g of total NaOH when adding CA in the calc.
- On soapcalc I get 34.87 g of total NaOH + manually adding the extra NaOH (3.75 x 6.24 /10 = 2,34 g) = 37,21 g.

The difference is 0.63. Is soapmakingfriend lye/soap calc using some other forumla?

 

[kagey]

okay -- so I'm going to take a stab at this (but I'll probably be wrong)

the amount of citric acid you can add = 1-3% of CA ppo
so you've got 250 grams = 2.5 - 7.5 gr of CA
(some places recommend no more than 2%...)
looks like you're using 1.5% CA ppo

then, were told:
10g citric acid neutralizes 6g of NaOH
(although some say: 1g citric acid = 0.624g NaOH)
either way, you have to compensate for this by adding MORE NaOH

Total lye required= Additional lye needed to accommodate for sodium/potassium citrate + lye needed to saponify recipe

so at 2.5g - 7.5g --- you're neutralizing 1.5 - 4.5g of NaOH
right?

so you have to add 1.5 - 4.5g NaOH to your original NaOH calculations
34.86 + additional lye = 36.36 - 39.36

both are answers are within tolerances.

a couple of things about your friend:
1.) it only goes one decimal point -- so you can't put in 3.75 (you'll have to round up or down)
2.) it asks if you're adding to lye, to oils or at trace
how you respond to these answers probably alters the formula & answer

so, yeah -- you soapmaker friend is not using the same formula as you - but you should be okay.

 

[cmzaha]

Remember all soap calcs can configure sap values a little differently since all have a buffer value and not exact Sap values. True Sap value per oil can not be known without testing each batch of oil. Also, I find it much easier to just multiply the total amount of citric acid to be used by 0.624. So if you are going to be using
250 x 0.015 =3.75
3.75 g citric acid x .624 lye = 2.34 additional lye + 34.86=37.2 Total lye
**I leave out the dividing by 10 to cut that step because I am lazy.**

 

[soapman5]

okay -- so I'm going to take a stab at this (but I'll probably be wrong)

the amount of citric acid you can add = 1-3% of CA ppo
so you've got 250 grams = 2.5 - 7.5 gr of CA
(some places recommend no more than 2%...)
looks like you're using 1.5% CA ppo

then, were told:
10g citric acid neutralizes 6g of NaOH
(although some say: 1g citric acid = 0.624g NaOH)
either way, you have to compensate for this by adding MORE NaOH

Total lye required= Additional lye needed to accommodate for sodium/potassium citrate + lye needed to saponify recipe

so at 2.5g - 7.5g --- you're neutralizing 1.5 - 4.5g of NaOH
right?

so you have to add 1.5 - 4.5g NaOH to your original NaOH calculations
34.86 + additional lye = 36.36 - 39.36

both are answers are within tolerances.

a couple of things about your friend:
1.) it only goes one decimal point -- so you can't put in 3.75 (you'll have to round up or down)
2.) it asks if you're adding to lye, to oils or at trace
how you respond to these answers probably alters the formula & answer

so, yeah -- you soapmaker friend is not using the same formula as you - but you should be okay.

Thanks, but does it matter if I put the CA in the lye water och in the oils?

Remember all soap calcs can configure sap values a little differently since all have a buffer value and not exact Sap values. True Sap value per oil can not be known without testing each batch of oil. Also, I find it much easier to just multiply the total amount of citric acid to be used by 0.624. So if you are going to be using
250 x 0.015 =3.75
3.75 g citric acid x .624 lye = 2.34 additional lye + 34.86=37.2 Total lye
**I leave out the dividing by 10 to cut that step because I am lazy.**

Well, you got the same answer that I did. So it is probably the SAP values that soapmakingfriend is using differently. I think that I will use soapcalc and add the CA calc manually. Thanks

 

[AliOop]

Thanks, but does it matter if I put the CA in the lye water och in the oils?

You absolutely must dissolve the CA in water (preferably warm) before adding the lye. If you don't dissolve it, it will be very scratching in your soap.

 

[soapman5]

You absolutely must dissolve the CA in water (preferably warm) before adding the lye. If you don't dissolve it, it will be very scratching in your soap.

Yes, but I was thinking if it is better to pour the CA water combo in the oils, stick blending them. Because of the strong reaction of NaOH and CA in the lye water

 

[TennisGirl]

I have no trouble adding CA solution to my lye water. Yes, the CA eats up some of the lye, but the soap calculator figures the extra lye for me. It doesn't make the lye water any hotter or anything like that, if that's what is concerning to you. But if you prefer to add it to your oils, you can certainly do that, too. People add all kinds of liquid to their oils, including milks, fruit purees, etc. Do what works best for your way of making soap.

 

[DeeAnna]

There is some heat created when citric acid and NaOH are mixed together. That heat is going to be created no matter what. You can't avoid that.

When you add citric acid to the fats, the chemical reaction happens in the soap batter. This means the heat created by the citric acid and NaOH reaction is entirely added to the soap batter. Your batter might get hotter than you would like which may accelerate trace or darken the color of the soap.

If you add the citric acid to the water that you use to make the lye solution, the heat generated from the citric acid and NaOH reaction is added only to the lye solution. You then have the option to let the solution cool before you add it to the fats, so you can more effectively manage the temp of the soap batter.

Irish Lass also found this to be true with honey. NaOH and honey react and generate heat. If you mix the honey with the water, and then add NaOH, the lye-honey solution gets hot, but you can then let it cool before using it to make your soap so the soap stays lighter in color. If you mix the honey into the fats or into the soap batter, the mixture heats up enough so the finished soap is darker.

 

[ResolvableOwl]

10g citric acid neutralizes 6g of NaOH
(although some say: 1g citric acid = 0.624g NaOH)

To make things even more complicated, that's the number for anhydrous citric acid. Actually, every quality of citric acid that I know/have bought was the monohydrate (with 8.6% crystal water). The conversion factor for it is 5.71 g NaOH per 10 g citric acid · H₂O.

I only right now learned that the SMFriend citric acid compensates NaOH, but their formula is indeed really weird. It treats citric acid as if it had a molar mass of 88 g/eq (per proton, i. e. 264 g/mol for the whole molecule), which doesn't fit either to the anhydrate (192) nor to the monohydrate (210). It would fit to a hypothetical tetrahydrate (never heard of it), a 72% aqueous solution (saturated solution at 60°C), but to neither of the customary powder forms.

 

[linne1gi]

There is some heat created when citric acid and NaOH are mixed together. That heat is going to be created no matter what. You can't avoid that.

When you add citric acid to the fats, the chemical reaction happens in the soap batter. This means the heat created by the citric acid and NaOH reaction is entirely added to the soap batter. Your batter might get hotter than you would like which may accelerate trace or darken the color of the soap.

If you add the citric acid to the water that you use to make the lye solution, the heat generated from the citric acid and NaOH reaction is added only to the lye solution. You then have the option to let the solution cool before you add it to the fats, so you can more effectively manage the temp of the soap batter.

Irish Lass also found this to be true with honey. NaOH and honey react and generate heat. If you mix the honey with the water, and then add NaOH, the lye-honey solution gets hot, but you can then let it cool before using it to make your soap so the soap stays lighter in color. If you mix the honey into the fats or into the soap batter, the mixture heats up enough so the finished soap is darker.

Also, the purpose of adding citric acid is to have the lye convert it to sodium citrate (a chelator) - it is best to add the citric acid to the lye water - to allow the lye to do its job.

 

[DeeAnna]

The alkali will react with citric acid whenever the two meet, whether that's up front in the lye solution or long after the soap is made. I know from having tried it that citric acid will decompose fully finished soap.

The main benefit of adding citric acid to the water for the lye solution is to manage the heat evolved.

 

[soapman5]

There is some heat created when citric acid and NaOH are mixed together. That heat is going to be created no matter what. You can't avoid that.

When you add citric acid to the fats, the chemical reaction happens in the soap batter. This means the heat created by the citric acid and NaOH reaction is entirely added to the soap batter. Your batter might get hotter than you would like which may accelerate trace or darken the color of the soap.

If you add the citric acid to the water that you use to make the lye solution, the heat generated from the citric acid and NaOH reaction is added only to the lye solution. You then have the option to let the solution cool before you add it to the fats, so you can more effectively manage the temp of the soap batter.

Irish Lass also found this to be true with honey. NaOH and honey react and generate heat. If you mix the honey with the water, and then add NaOH, the lye-honey solution gets hot, but you can then let it cool before using it to make your soap so the soap stays lighter in color. If you mix the honey into the fats or into the soap batter, the mixture heats up enough so the finished soap is darker.

Thank, I now too think that it is better to add in the lye water. There is a color change and hotter soap if added to the oils!

 

[soapman5]

To make things even more complicated, that's the number for anhydrous citric acid. Actually, every quality of citric acid that I know/have bought was the monohydrate (with 8.6% crystal water). The conversion factor for it is 5.71 g NaOH per 10 g citric acid · H₂O.

I only right now learned that the SMFriend citric acid compensates NaOH, but their formula is indeed really weird. It treats citric acid as if it had a molar mass of 88 g/eq (per proton, i. e. 264 g/mol for the whole molecule), which doesn't fit either to the anhydrate (192) nor to the monohydrate (210). It would fit to a hypothetical tetrahydrate (never heard of it), a 72% aqueous solution (saturated solution at 60°C), but to neither of the customary powder forms.

Well that is also true, so becuase of this. I bought some cheap sodium citrate, and no more counting!

 

[ResolvableOwl]

Yes, that's clever (and sufficient unless you also use the citric acid for liquid soap, bath bombs, kettle descaling or soft drinks).

 

[Tara_H]

Yes, that's clever (and sufficient unless you also use the citric acid for liquid soap, bath bombs, kettle descaling or soft drinks).

(I'm pretty sure I got mine for spherification, but I can't seem to find the recipe any more )

 

[ResolvableOwl]

Molecular kitchen: the art of abusing drill fluid additives for culinary delights.

 

[Justcallmewillie]

Hello, I was using soapmakingfriend lye/soap calc to calculate the total amount of NaOH when including citric acid, but when I compared it to soapcalc + calculating the added amount of NaOH manually, i get different numbers. The batch is 250 grams of oils and the amount of CA is 1.5 %, SF is at 3 %, lye conc is 33 %.

The formula for manually adding CA is (Citric acid weight, grams) X 6.24 / 10.

- So on soapmakingfriend lye calc I get 34.86 g of NaOH without adding CA in the calc and 36.58 g of total NaOH when adding CA in the calc.
- On soapcalc I get 34.87 g of total NaOH + manually adding the extra NaOH (3.75 x 6.24 /10 = 2,34 g) = 37,21 g.

The difference is 0.63. Is soapmakingfriend lye/soap calc using some other forumla?

Thank you for making this post! I was wondering the same thing just now. And some of these popular calculators Don’t say exactly how much CA is needed either