Cutting Soap?

[Miba]

My soap always crumbles when I cut it, it doesn't matter what recipe I use, it always happens. Straight shortening. Shortening and olive oil. Shortening, olive, peanut. Shortening, olive, peanut, coconut. It all crumbles. I always use more shortening than anything else, because I figured that would give it a strong base? I've never followed a recipe exactly, I always branch off and do my own thing using the MMS calculator.

I live in a very high altitude area and it's very dry here. This last batch I made I let it stay in the mold overnight and cut it this morning (as opposed to waiting three days) and it still crumbled. So my theory that it might just be the dry air is out.

Maybe it's the knife? What kind of knife should I use? I hear some people use wire or fishing line? Is there a certain technique used in cutting? Do you saw or push straight down? I've used a few variety of knives and I saw.

I always use the MMS calculator. I don't have a scale of any kind, though I will be getting one very soon here. I use the "ounces" mark on the pyrex I use as a guide for the water and lye, and then I use an "ounces to cups" chart to know how much fats to put in. My soap's quality has always been great, I love the quality, so I thought whatever little difference there is between how I measure and how you're supposed to measure wasn't bad. But could there be that much of a difference and that's why my soap splits apart?

Here's a picture of my current failure at cutting, and this is the same kind of crumbling I always get. These two are the worst of this batch, and I don't always make round soap. I used to make it in a bread pan and then cut into rectangles... or rather I tried to cut them into rectangles. And it has gotten better, my first attempts at rectangles turned them more into semi-triangles. http://1.bp.blogspot.com/_oW6rbDnbQnI/TURV-5CVhXI/AAAAAAAAAPI/IMdaGGuoqd0/s1600/100_1004.JPG

[Starr]

It could be a lot of things but I doubt it's the dryness of your air. It could be a measuring issue or a recipe issue or a mixing issue even. It could be a cutting issue as well. I've never had to saw at any of my soaps. I've used straight and wavy cutters and occasionally just say "whatever" and have grabbed a knife (I have a special cheapy yard sale set I bought just for crafts). Typically, you push straight down and it should go through pretty easily. I suspect there's too much hard oil in your recipe especially if you're using that high of a shortening content. I would suggest putting your recipe through soap calc or a similar calculator and checking it out, even a few ounces off can cause a major difference. If you've got a scale coming in, that's even better. Measure by volume isn't terribly accurate, even a lot of chefs and cooking guru's have changed over to measure by weight. When I'm measuring my water for example, I often use a glass measuring cup as a guide. If it calls for 6oz of water, I'll fill the cup roughly to the 6oz marker then weigh it and add/subtract as needed, 6oz by weight and 6oz by volume are always different. With a scale on the way, those are two very easy things you can try to help fix the problem that you're having. When you do cut, try cutting larger bars, sometimes if you're cutting thin ones, they're more prone to breaking.

HTH

[Miba]

I have actually never used a soap calculator. I found one that included shortening on it and the ounces it came out with were different than mine, if only slightly.

Also, maybe I should try cutting back on the shortening, then? I'm not attached to that idea, but it would make sense since that is one of the things that's the same about all my batches. I should try to make it more balanced between hard and liquid fats?

I'll wait until the scale gets here before I try again, though.

[Faerywren]

A straight shortening soap would be very soft and mushy. I would guess your problem would be the fact you dont use a scale. You should be using weight not volume. 8 oz on a measuring cup doesn't weigh 8 oz.

[Starr]

Faerywren, correct me if I'm wrong but I thought a lot of shortening was including Palm nowadays. Admittedly, I haven't used it in my soap in... well, too long and I never liked it so it wasn't something I used for terribly long either. I thought I remembered it adding hardness. Maybe I'm thinking of something else.

Miba, a good rule of thumb (which can and is broken from time to time) is to try for roughly a 50/50 split between liquid and solid oils.

Edited January 29, 2011 by Starr
typo

[LuminousBoutique]

it does have palm (crisco) but not enough to make up for ALL that soybean... imo... if you're using MOSTLY crisco. Shortning could be so many thing.. animal/veg mix.. all veg... veg and palm... what brand are you using Miba?

Is your soap gelling?

You absolutely need a scale, and to run your recipe through a soap calculator, to make proper soap. Once you get that, you will be alright!! And you have your process down... so it should be a snap from here

[CareBear]

I use the "ounces" mark on the pyrex I use as a guide for the water and lye, and then I use an "ounces to cups" chart to know how much fats to put in. My soap's quality has always been great, I love the quality, so I thought whatever little difference there is between how I measure and how you're supposed to measure wasn't bad. But could there be that much of a difference and that's why my soap splits apart?

Yes, there could be. Clearly something is going on, and I'd suggest starting by measuring accurately. Who knows - you may find that the great quality soap improves by leaps and bounds.

[jonsie]

I'm still new to soaping so I can only agree with what the other people have said here in this thread... use something like SoapCalc, and use a scale.

I am also curious if crumbling soap means the lye water and the oils are mixed at too high of a temperature? Hopefully the veterans can set me straight on that.

[Miba]

Thanks, all of you. I guess it does make that much a difference. I will use the scale from now on. It's actually my mom's scale, but she doesn't really use it much and is coming into town today and will bring it to me. It's a postal scale, and she only used it for seeing how much to charge for shipping on things she sold on ebay.

And I messed around with that Soap Calc thing, looking at different things, and it was really neat.

I guess I'm still more of a newbie than I thought, though at least, like LuminousBoutique said, I've got the process right, now I just need right technique. Oh, and in answer to your question, I was using Crisco All-Vegetable for this last batch, but I was using Kroger brand before that.

And in response to Jonsie, I wait until both the lye and fats are around 100-110 before mixing.

Edited January 30, 2011 by Miba

[Faerywren]

Faerywren, correct me if I'm wrong but I thought a lot of shortening was including Palm nowadays. Admittedly, I haven't used it in my soap in... well, too long and I never liked it so it wasn't something I used for terribly long either. I thought I remembered it adding hardness. Maybe I'm thinking of something else.

Miba, a good rule of thumb (which can and is broken from time to time) is to try for roughly a 50/50 split between liquid and solid oils.

Some shortenings are soybean and cottonseed oil. No palm at all. The resulting soap would be soft, mushy and slimy.

[IwantItgreen]

Different oils add different properties to your soap but it has to be balanced. May I recommend a search here on using these keywords "fatty+acid". You will learn a lot about what makes good soap.