new lye = overheated soap?

[CanaDawn]

Hi there, I've been following this forum for about a year, but have just subscribed because I couldn't find the answer to my newest soap question here or online:

I just started using different lye, and suddenly I have cracking and gelling where I haven't before (same recipe, same mold, same water, same kitchen, same everything except the lye)

I was using lab grade NaOH, and then bought plumbing lye from a local hardware store that says free-flowing 100% lye. The sales clerk knew where it was because "lots of people are making soap with it", so it is being used for this purpose.

What could be causing the partial gel and cracking? I soaped at around 75C, but as I say, this is normal operating procedure for me. I didn't cover the last two batches to see if that would help....no.

The soap itself is fine, but I'm curious why the change has occurred.

 

[Iluminada]

I had been making soap successfully from day one until one day all 3 batches I made caused a volcano. That day was very odd because it seemed like I was waiting less time for the lye and oils to cool down. But never the less I mixed it and by the time I turned around with the plastic wrap to cover it up.....volcano. It happened 3 times in one day. Out of curiosity, I took my spare thermometer out and realized that the thermometer I was using was off by 20 degrees. So you may want to check the thermometer out.

 

[lsg]

You might also check your scale.

 

[CanaDawn]

ok, will check both of those things. I'm pretty casual about soaping temp anyhow, but I have two new digital scales (santa obviously forwarded my list around), and have made one batch with each of those two scales with the same result. I'd be surprised if both scales were equally off.

I also have two different thermometers (use one in oils, one in lye) that I don't specifically assign to their task, so the odds are very low of me using the same thermometer everytime in the same component.

As I say, the only real change has been the lye. I just don't understand why.

I'm pretty casual about soaping temp

To clarify, usually on the side of "low". (I think...from my own reading anyhow..am I wrong about this?)

 

[CaraBou]

75 C is 168 F, pretty hot in my book. Perhaps you were previously reading the Fahrenheit side of the scale and inadvertently switched to the Celsius side?

 

[CanaDawn]

ok, yes, misread F as C, but have been doing so consistently all along. (don't do much in F around here, didn't even think about the fact that 110C would be boiling the water...*sigh*) But still....have been soaping exactly the same way for a couple of years, and this is a new event. That's the weird bit. I will reduce the temp to see if that changes things.

 

[CaraBou]

I bet it will help you avoid the situation in the future even if it doesn't explain the difference. I normally bring my lye and oils down to about 80-90 F (27-32 C) before combining, but then encourage gel through insulation if I don't have sugary additives or an FO I am unsure of.

A common way to do CPOP (cold process/oven process) is to put the oven on as low as it will go -- 170* F (77 C) for most in US-- turn the oven off in an hour or so to bring the soap to full gel, and then let it sit in there awhile longer, usually > 1 hour longer. So I'd guess that temp is okay for most soaps, but anything with additives always runs risk of overheating.

As for your hardware lye... I obviously can't speak for the batch in your possession, but I can say I have soaped exclusively with this kind of lye since I started making soap 2 1/2 years ago, I've never had cracking or other obvious overheating during CP soapmaking. Hardware lye is all I can get here, and for a long time I resisted mail ordering anything to avoid getting raked on shipping charges. So at this point I'm pretty comfortable with it. One day I am going to order food grade lye though, because I want to make pretzels!

 

[seven]

i too have been using the cheapest grade of lye and it never gave me any problem. you might want to lower your temp, 75c is pretty darn high.

 

[Susie]

Could it be possible that your old lye was indeed old? I mean old enough to have soaked up a bit of humidity, not like years old.

I live in a high humidity area, and have taken to weighing my lye bottle when I finish using it so I will know when it soaks up moisture. I then write the weight on the bottle so I can weigh it when I go to use it again. I had to toss about a pound of lye due to how much more it weighed when I went to use it again. And I do store it inside, in air conditioning, in the original bottle, then in a Ziploc bag with silica gel packets tossed in. If I had another soaper nearby, I would share lye with them so as not to waste any more.

 

[pamielynn]

I will tell you that this has happened to me. I switched lye suppliers once and every single batch I made with it did something wonky. Everyone told me it couldn't be the lye. Ordered some from my original supplier and everything went back to normal.

Sadly, I had ordered 50 lbs from the new supplier - but found a local soaper and traded for some butter she had Have stayed with my original supplier ever since.

 

[CanaDawn]

I did wonder if the lye were just more concentrated/less humid. I'm not worried about the quality of the lye but lab grade is going to be different to food grade and to hardware plumbing grade!

pamielynn, at least I'm not alone it's the only thing that has changed.

My oils are basically never that hot, so probably the actual soaping temp is less than 75, but I am happy to try lower. I never worried about it because what I was doing was working and making me all the soap I need. It's funny that I never had gel before this lye (and other than my first batch, which volcanoed spectacularly before going on to be decent soap, no cracking either.)

 

[CanaDawn]

Of course, having one problem, I'm about to try a different recipe. The last batch that cracked and gelled is out and seems just fine. I'm curious about trying some different butters, as I generally just do CO or the occasional bit of castor or olive. The one batch I did with CO, shea and cupuacu I didn't like nearly as much as the CO.