Scaling up your recipe

[ewhitake]

I have a recipe that I really like and I wanted to scale it up a salt soap recipe that proves very successful. The photographs show you the small batch and the large batch recipes. The large batch still hasn’t hardened and it’s been more than 24 hours. It’s soft, and there’s a lot of insaponified oils. The loaf feels greasy to the touch.
If all I did was increase the volume shouldn’t the results of been the same?

 

[Mobjack Bay]

Something is off. I’m on my phone so can’t offer much, but it looks like oil weight increases from 393g to 1518g, nearly a factor of 4 (3.86), while lye is only doubling from 110g to 212g.

 

[bookworm42]

I noticed that in recipe 2 it calls for a master batch vs the other recipe just says NaOH weight. Did you use a master batch this time? If so maybe you didn't have enough lye.
I also noticed that you used sodium citrate. Do you use sodium citrate or citric acid?

 

[Mobjack Bay]

Oh, I missed that it was master batch lye for the first recipe. So the calculated lye amounts are likely both okay, but as @bookworm42 mentioned, possibly you used 212 g of MB rather than 424g of MB. I’m assuming your MB is 50% lye concentration.

 

[ewhitake]

I noticed that in recipe 2 it calls for a master batch vs the other recipe just says NaOH weight. Did you use a master batch this time? If so maybe you didn't have enough lye.
I also noticed that you used sodium citrate. Do you use sodium citrate or citric acid?

I use sodium citrate

Oh, I missed that it was master batch lye for the first recipe. So the lye amounts are likely both okay, but as @bookworm42 mentioned, possibly you used 212 g of MB rather than 424g of MB. I’m assuming your MB is 50% lye concentration.

I hadn’t noticed the difference with the lye. And I had thought somehow there was a problem with the lye that I didn’t catch.

 

[DeeAnna]

The other issue that can be overlooked is when you scale up, you have to scale up the amount of mixing. You say the larger batch shows some signs that it wasn't mixed well which is a clue. If you mixed the larger batch for about the same amount of time and with the same type of mixer, it's probably wasn't as fully emulsified as the smaller batch.

Let's say I put X units of energy into Y units of soap batter. I then scale the batch up 4 times larger. When I make that larger batch, assuming all other things are equal, I will need to put more than Y units of mixing energy into that batch. This can be done by using a more powerful mixer or mixing for longer or both.

And also a larger batch will heat up more during saponification than a smaller batch if you're using a large mold to contain all the batter from the larger recipe. This can result in overheating in the mold -- that can lead to emulsion failure, separation, or cracking.

 

[Ekuzo]

I hadn’t noticed the difference with the lye. And I had thought somehow there was a problem with the lye that I didn’t catch.

If you used MB for the small batch and NaOH for the big one, it's all good. BUT if you used MB for both batches without adjusting the NaOH for the big batch - you got soap with two times less NaOH than needed (leading to lots of unsaponified oils, as you observed) plus 25% more water than needed for the recipe. IMHO, you would need to rebatch it to save it, adding the missing NaOH to it

 

[ewhitake]

If you used MB for the small batch and NaOH for the big one, it's all good. BUT if you used MB for both batches without adjusting the NaOH for the big batch - you got soap with two times less NaOH than needed (leading to lots of unsaponified oils, as you observed) plus 25% more water than needed for the recipe. IMHO, you would need to rebatch it to save it, adding the missing NaOH to it

Hummm, you make a lot of good points but shouldn't the soap calc make the adjustment? Now that I'm thinking about it, I've had the same problem before when I tried to scale a recipe to this specific large mold. Maybe if I look up the manual way to calc the lye I'd have better success?

The other issue that can be overlooked is when you scale up, you have to scale up the amount of mixing. You say the larger batch shows some signs that it wasn't mixed well which is a clue. If you mixed the larger batch for about the same amount of time and with the same type of mixer, it's probably wasn't as fully emulsified as the smaller batch.

Let's say I put X units of energy into Y units of soap batter. I then scale the batch up 4 times larger. When I make that larger batch, assuming all other things are equal, I will need to put more than Y units of mixing energy into that batch. This can be done by using a more powerful mixer or mixing for longer or both.

And also a larger batch will heat up more during saponification than a smaller batch if you're using a large mold to contain all the batter from the larger recipe. This can result in overheating in the mold -- that can lead to emulsion failure, separation, or cracking.

Good point! I think I got to a medium light trace before stopping thinking I was over doing it. LOL!!
When you talk about heating up with large batches, how do you combat this? Just work in smaller batches?

 

[dmcgee5034]

Hummm, you make a lot of good points but shouldn't the soap calc make the adjustment? Now that I'm thinking about it, I've had the same problem before when I tried to scale a recipe to this specific large mold. Maybe if I look up the manual way to calc the lye I'd have better success?

I’m still not clear on your lye for the larger batch 2, to understand the calc adjusting for you. Did you use MB lye for the larger batch? It looks like no, based on your print out. Perhaps when you scaled up, you missed the MB lye toggle? Sorry this happened to your soap.

 

[ewhitake]

I’m still not clear on your lye for the larger batch 2, to understand the calc adjusting for you. Did you use MB lye for the larger batch? It looks like no, based on your print out. Perhaps when you scaled up, you missed the MB lye toggle? Sorry this happened to your soap.

Yeah, I think it had something to do with how much lye I didn’t add to the soap. I should’ve been able to spot it myself, but sometimes you need an extra set of eyes. Thanks!

 

[Ekuzo]

Yup, what @dmcgee5034 said. If you didn't select 'using master batched lye' (or something similar in the calculator) for the big batch, it just gives you the weight of the NaOH in flakes or pearls (or whatever you are using, but in dry, undissolved condition, with no water added). Meaning that if the recipe called for 200 gr NaOH and you added 200 gr master batched lye solution instead, you used only 100 gr of NaOH instead of 200 gr (assuming you use 50% lye solution for MB). And that way you added more water than needed as well.

 

[ewhitake]

Yup, what @dmcgee5034 said. If you didn't select 'using master batched lye' (or something similar in the calculator) for the big batch, it just gives you the weight of the NaOH in flakes or pearls (or whatever you are using, but in dry, undissolved condition, with no water added). Meaning that if the recipe called for 200 gr NaOH and you added 200 gr master batched lye solution instead, you used only 100 gr of NaOH instead of 200 gr (assuming you use 50% lye solution for MB). And that way you added more water than needed as well.

Thanks!! Just need to be more careful

 

[Ekuzo]

Thanks!! Just need to be more careful

On the bright side - you will learn how to rebatch your soap, if you haven't done it until now

 

[ewhitake]

On the bright side - you will learn how to rebatch your soap, if you haven't done it until now

Yeah - I've was just thinking about that. My "bad soap" box is overflowing now. But I don't have a pot or a slow cooker that's dedicated to soap. They should be dedicated to soap...right?

 

[2lilboots]

@ewhitake you will end up having several dedicated soap containers . I know I do.

 

[Ekuzo]

Yeah - I've was just thinking about that. My "bad soap" box is overflowing now. But I don't have a pot or a slow cooker that's dedicated to soap. They should be dedicated to soap...right?

Yup, it's better if you use that one for soap only, to avoid any mix ups

 

[bookworm42]

I'd pick up a cheap slow cooker/crockpot from somewhere.
I got one for $20 in college and it still works great. It's now used for soap and my husband gets a bigger crockpot to make his rice and beans in.

 

[AliOop]

Yeah - I've was just thinking about that. My "bad soap" box is overflowing now. But I don't have a pot or a slow cooker that's dedicated to soap. They should be dedicated to soap...right?

Nope, no need to dedicate your crockpot or your stickblender to making soap.

After all, when you are done cooking food in your crockpot, or blending some food with your SB, what do you use to wash it?

I will say that if you plan to sell your products, GMP would be to have dedicated soaping equipment. But that's more to make sure that you don't get food or food-related allergens in your soap, rather than the opposite.

 

[Ekuzo]

My SB, for example, cannot be disassembled, and being hand washed - there's always a tiny bit of soap residue left inside the bell, which usually doesn't bother me. I'd say, stick to dedidacted vessels and tools - you don't want soap in your cake.

Also, I think having traces of undiluted EO and FO (nobody is safe from undermixing a batter) on your vessel's surface can sometimes be even more dangerous than having traces of lye - and you don't want that. JM2C, better safe than sorry.

 

[2lilboots]

@Ekuzo the FOs and Micas are the reason I keep my soaping containers separate from my cooking/baking stuff.