Using Sour Milk in Soap

[Astro]

Hi
I am quite new to soap making and absolutely loving it. I have used a basic hot process recipe to learn (recipe below) and made 2 batches so far. The first was as instructed without the EO. The 2nd I halved at thick trace and moulded for cold process and then added lavender EO and food colour to the rest of the batch for hot process - all have come out amazing and really nice although I did have a little trouble unmolding the cold process (probably needed longer in the mold)
I live on a farm where we produce jersey milk and a faulty freezer has resulted in 150 litres of un-pasteurised, un-homogenised milk going sour. I have found a couple of basic milk soap recipes that I would like to try . Again, I am going to split the batch for cold process and then hot to see the difference. I will freeze the milk for the lye solution.
Now for the question: The milk is separating as it sours, and I have the solids at the top and whey below. How should I process this mixture as the liquid content of the lye?
1. Should I whisk it all together to try and get a more milky consistency
2. Should I use the whey as the liquid for lye and add the solids into the weights for the oils/solid fats
3. Can I just use it as it is or do I need to make adjustments for the solids and liquids.

Can anyone advise how I should use the milk. Thanks

The recipe I want to try is

• 10 ounces milk (try 9 oz if you want your soap to set up faster, or if using silicone molds)
• 4.3 ounces lye (sodium hydroxide)
• 22 ounces olive oil (71%)
• 8 ounces coconut oil (26%)
• 1 ounce castor oil (3%)

Here is the original recipe I started making soap with:
• 36 oz. olive oil (emollient and gentle)
• 6 oz. coconut oil (helps make a good hard bar)
• 3 oz. castor oil (improves suds)
• 6 oz. lye
• 12 oz. water
• 2-4 oz. essential oil of choice, optional

 

[Relle]

Welcome Astro . As this is your first post, please go to the Intro forum and tell us a bit about yourself.

 

[Astro]

can anyone help me with this please?

 

[artemis]

A lack of response might mean that no one has experience using soured milk.

Why not try using the whey in place of water? Maybe stick blend a small amount of solids into the oils?

 

[shunt2011]

Okay, I just now saw this. I have used buttermilk in soaps with no issue. Buttermilk is pretty much soured milk.

 

[Arimara]

You would have to weigh the solids and run it through a calculator to get the sap values for the milk fat. As for the whey, you could just use it as your liquid but adust your superfat accordingly. Overall, I personally advice you to make as small a batch as you can safely make because I imagine that you might make a stinky soap.

 

[Astro]

Thank you for your feedback. I decided to try anyway and froze the milk by weight ignoring the ratio of milk solids to whey and treating it as whole milk. I also split the batch into 3 and added a little liquid food colouring to 2 parts to see whether I could get a swirl of sorts. That didn't work quite as expected but I am not unhappy with the results. Should I have gone to a thicker/thinner trace to get more defined lines? I think I will call it Milkshake (Photo below).
By ignoring the milk fats to Whey ratio I am assuming that my actual superfatting % could be more than 5%. How will this affect the soap and will there be any significant difference. I also know that afternoon milk from the herd contains considerably more cream than morning milk - should I factor this into my calculations in any way?
Thanks again for the feedback.​

 

[Astro]

You would have to weigh the solids and run it through a calculator to get the sap values for the milk fat. As for the whey, you could just use it as your liquid but adust your superfat accordingly. Overall, I personally advice you to make as small a batch as you can safely make because I imagine that you might make a stinky soap.

I am not sure why, but even the milk did not smell off and was only separating so, fortunately, the soap smells just like soap. I am guessing but the only logical reason for little smell in the milk that I can think of is that it is unpasteurised and unhomogenised

 

[amd]

I am guessing but the only logical reason for little smell in the milk that I can think of is that it is unpasteurised and unhomogenised

Actually, pasteurized milk in soap will produce little smell. I've done several comparisons making my own goat milk soap with pasteurized milk (soap had no vomit smell), and comparing to soapmakers I know use raw milk (soap has vomit smell). Most people don't seem to even notice the smell, so I suspect some of it is my own sensitive nose, but even buttermilk (pasteurized) has never given me a problem with smell.

 

[penelopejane]

Thank you for your feedback. I decided to try anyway and froze the milk by weight ignoring the ratio of milk solids to whey and treating it as whole milk. I also split the batch into 3 and added a little liquid food colouring to 2 parts to see whether I could get a swirl of sorts. That didn't work quite as expected but I am not unhappy with the results. Should I have gone to a thicker/thinner trace to get more defined lines? I think I will call it Milkshake (Photo below).
By ignoring the milk fats to Whey ratio I am assuming that my actual superfatting % could be more than 5%. How will this affect the soap and will there be any significant difference. I also know that afternoon milk from the herd contains considerably more cream than morning milk - should I factor this into my calculations in any way?
Thanks again for the feedback.​

View attachment 44296

Thinner trace for wispy swirls.
If you don’t want to bother with calculations drop your recipe SF to 1 and you’ll end up a bit higher with the milk. High SF can cause the soap to go a bit gluggy half way through the bar and can clog your drains and too high can sometimes lead to DOS if your hygiene practices aren’t 100%.

 

[Arimara]

I am not sure why, but even the milk did not smell off and was only separating so, fortunately, the soap smells just like soap. I am guessing but the only logical reason for little smell in the milk that I can think of is that it is unpasteurised and unhomogenised

I was under the impression you were using souring milk but since you're using a milk I'd have to trek a state over to smuggle (a couple of states really), I made my reply with that in mind.

 

[Astro]

I was under the impression you were using souring milk but since you're using a milk I'd have to trek a state over to smuggle (a couple of states really), I made my reply with that in mind.

it was definitely sour milk but it didn't have the awful sour milk smell

 

[Arimara]

it was definitely sour milk but it didn't have the awful sour milk smell

Oh, ok then. Give it time and see.

 

[BirchandTallow]

I realize this is an old thread, but I'm new to the forum and found the question interesting. I had some expired milk (about 10 days past expiration and pretty smelly, but not chunky), and decided to batch with it. I was at the end of my sodium hydroxide bottle, so I used a water to oil at 38%; SF at 9%; lye concentration at 25.7%; and water:lye at 2.9:1.

64.5% Beef Tallow
19.5% Ollive Oil
10% Coconut Oil
4% Castor Oil
2% Coco Butter

I poured at a very very light trace and let it sit for a full 24hrs. I have to say, it unmolded beautifully, gelled perfectly, and has a gorgeous smell of sweet cream with a hint of coco. I love that I didn't pour that sour milk down the drain. Thanks for the idea. Photos attached.

 

[Zany_in_CO]

Well done! Sour Milk Soap! Who woulda thunk it?! Certainly not me.
Thanks for sharing!

 

[GGMA0317]

Well done! Sour Milk Soap! Who woulda thunk it?! Certainly not me.
Thanks for sharing!

Atp nothing surprises me in the world of soapmaking. I was done when I saw bacon in soap. Then there's dried botanicals and oatmeal sitting on top of soap. Soap that looks like slices of pie or cake. Sour milk is pretty tame when you realize that somewhere there's probably a dirt bar with bacon on top, dipped in beer. Yup, a dirty drunken bar of soap that smells like...Pointless. If you look up, "doing too much" you'll find a soaper. I guarantee it.

 

[BirchandTallow]

A couple of things..... Its been 2 months and the sour milk soap turned out PHENOMENAL! As cheap as it was to make (about $8 for 5lbs), it's actually become my favorite soap.
It's a gentle clean that's strong enough to cut through store bought deodorant but still leaves my skin super soft. Like, softer than any other recipe I've made so far including those with sweet cream or goat milk. I've cut the big bars in half and given quite a bit away, but I'm attaching a photo of what's left on the shelf for your viewing pleasure. Then,..... I'm posting again to show you what happened with batch #2 that was attempted yesterday. *suspenful music plays*

 

[BirchandTallow]

So, Saturday I cleaned out the fridge and noticed we were at the end of the milk and it was expired. I put it on the counter with every intention of soaping with it, and then totally forgot it was there. Sunday morning, I saw the milk on the counter, remembered my plan. I put it back in the fridge to get cold for soaping. A few hours later, I started a batch. I had every intention of repeating the first recipe exactly....but I ran out of beef tallow. No problem, I subbed what I was short for goat tallow. Soapcalc confirmed it was a negligible difference so we're good to go. Then, I over poured a little on the sour milk. Well, too much liquid is better than too little, right? So, no big. Everything else seemed to go without any issues and before long the batter was in the mold. I remembered that the 5lb batch was a little soft after 12hrs last time, so I waited a full 24hrs this time....and...it...OOZED!!! OMG it was SO gross coming out of the mold. I knew pretty instantly the batch was trash, but the ooze was just mesmerizing. Idk why, but I was so excited about the fail I couldn't wait to cut it open and make a huge mess! I put it in a thick cardboard box with lots of packing paper and cut it in half. Holy cow, the smell. I'm pretty sure leaving the milk out was where I went wrong. Expired milk only works if it's kept in the fridge until used. What a powerful smelling lesson. Photos attached for your gawking pleasure.

 

[Zany_in_CO]

So sad! Ain't that just the way it goes? Once you think you've got something down pat, the soaping gods come along and totally smack you back down. SHEESH!

Um, general rule of thumb... wait at least 2 weeks before deciding what to do with it...
Maybe try @DeeAnna's Salting Out process? Might be fun? Might eliminate the smell? Might rescue enough soap to make saving it worth while?

 

[BirchandTallow]

Very interesting suggestions
But this round it all went in the dumpster. I was out voted and forbidden from keeping it lol.