Increasing shelf life... help!

[Chaiat5]

Hi friends!

I had made Zany's Castile soap prior to visiting my family in Singapore and asked my SIL to babysit the bars while they were curing. They were not too bad, I thought but just recently, I found some DOS. I had placed the soaps in a cool part of the house, away from sunlight etc. and the oil was a freshly opened bottle and not expiring. I am not sure what happened. I am trying again and hoping this time to add something to preserve the shelf life:

1. Rosemary oleoresin and grapefruit seed extract are not available here, it seems. Vitamin E oils is a little pricey, I think.
2. I can get EDTA and citric acid... which would you recommend for Zany's recipe? I need to increase my lye for CA, yes? Anything I should look out for with EDTA?

I am still making small batches but I think I'll cry if I waste another lot of olive oil Thank you so much!

 

[Ekuzo]

Just to make sure, the soap was not cured on a metal rack, right? And you used distilled/deionized water only?

I haven't used EDTA, grapefruit seed extract or vitamin E. ROE is a good choice for soap high in liquid fats if you can get it (you said you don't have it locally, unfortunately). You need a really small amount of it to be effective, but it's usually expensive.

Using citric acid as a chelator is something a lot of us do - some people even buy sodium citrate which is what you get in the end when the acid reacts with the NaOH. Citric acid is widely available and usually cheap.

Yes, you need to recalculate the recipe a little if you use citric acid (some people don't, it usually adds a little bit of superfat to your recipe). If you are curious about trying that, this lye calculator automatically calculates the additional lye needed when you add citric acid and adds it to the recipe, so you don't need to do it yourself. In case you want to use another calculator, use the following info:

10 g citric acid neutralizes 6.24 g NaOH. 1g ca=0,624g NaOH

10 g citric acid neutralizes 8.42 g KOH. 1g ca=0,842 KOH

That way you can calculate how much NaOH you need to add to compensate. Those numbers are taken from DeeAnna's website - https://classicbells.com/soap/citricAcid.asp

 

[Chaiat5]

Thank you so much! This is so helpful

I was careful with the water and I did not cure on a metal rack. I can't for the life of me figure out why there was DOS … it was so disheartening, but I’m trying another small batch of Castile soap tomorrow. I’ll keep your tips in mind!

 

[Ekuzo]

I'm glad you found it helpful!

We all have access to different products, and there could be differences between batches as well - so the olive oil I use can be really far from what you have. Even if the oil is fresh and you were careful taking all the measures against DOS, the soap can still act funny. The fatty acid profile can be a little far from what you get in the calculator and that can make a big difference.

I have issues with DOS when I use sunflower oil (regular), even if only at 10% of oils. No matter what I do. And then again, there are people on the forum who use higher % sunflower oil in their recipes with no issue. Soaping is not an exact science. I mean, it can be, but most soap makers don't have access to the lab environment and tools to make sure each and every batch turns out exactly the same, unfortunately. Experiment and stick to what you like, along with the disappointment there will be lots of success!

 

[Chaiat5]

You’re right —it’s hard to say how the oil will behave. It’s odd that the olive oil soap I took so much care with developed DOS and the soap I made out of repurposed cooking oil didn’t!

 

[Ekuzo]

What do you do with the used oil before you can make soap with it? Do you just strain it or do you clean it additionally?

 

[Chaiat5]

I did the following:

• strained several times through a sieve and cheese cloth
• poured in a layer of flour to push down the impurities and then pouring again through a cheese cloth, leaving behind the flour and gritty bits
• heat with ginger and lemon grass to remove the smell

I am still experimenting The oil I had wasn't very dirty or heavily used, but next time, I will boil with water and cornstarch.

 

[Ekuzo]

Wow, that's a lot of effort! Thanks for sharing - I've never tried it but I was curious. And how is it, do you notice any difference between that and soap made with fresh oils?

 

[Chaiat5]

Well, it was actually not bad... I have no idea what the mixture consisted of (I asked friends to donate their oil since I don't deep fry much) but I am guessing canola, sunflower and some olive oil. The soap was firm and had a nice amount of suds ... there was just a slight slimy feeling in only one or two bars. No bad smells whatsoever... I used mint EO so it was all quite pleasant. I think though I should have added a bit of coconut oil in the mix just to harden the bars more. I used the soap for general kitchen cleaning (not for bathing!) — I'd hand wash some cleaning cloths etc and the soap didn't dry out my hands at all.

 

[Ekuzo]

Oh, so you used only the liquid mixture and didn't add any other oils, and it was fine, like a castile soap? Nice!