CP soap gained weight!

[PuzzledSoapmaker]

Hi guys,

I know that a common method to check whether a CP soap is done curing is by weighing it - once it stops losing weight, aka the water stops evaporating, you're good to go.

Now, I'm having a pretty unusual issue, at least I haven't heard of it before. My soap was made with 1.1 : 1 water-lye ratio, so I expected it to cure shorter than a month. For the first 9 days or so, the soap was losing around 0.2 g a day, but today is the second day that it actually gained weight.

Does anyone have an idea what could be happening and if I should be worried?

Thanks in advance.

 

[AliOop]

Did you use a hydroscopic ingredient like Dead Sea Salt or Epsom Salt?

Without knowing all details of your recipes (amounts of all ingredients, including additives, oils, water, and lye), it is really hard to even guess what might be happening.

 

[NewlyCreative]

How much weight is your soap gaining per day?

 

[Garden Gives Me Joy]

I weighed the soaps when I poured them into single-bar molds. I then weighed them at different times where the only thing that changed was the time. The bars just remained in the molds. In addition to seeing that the soaps were sweating, their weights continued to rise with time once they cooled down. Examples:

Soap 1:

• at pour: 56 g
• day 6: 56.9 g
• day 17: 57.7 g

Soap 2:

• at pour: 53 g
• hour 1: 52.9 g
• hour 4.5: 52.7 g
• day 6: 53.7 g
• day 17: 54.6 g

[...]
I was trying to go to extremes with high mixing temperatures and the hot water bath and would push the envelope further if it were possible to do so with good results.

I had this issue with my hydroscopic (brine) soap ... that I made in a highly humid tropical rain forest climate. As you can see, I got some weight gains of about 3% when the rains were just beginning by day 17 after pour.

For that brine soap, I do what I call "WARM PROCESS" (neither cold nor hot process). I now have 'WP' in my instructional notes. A key objective is to evaporate away as much water as possible before the soap can gain weight in my highly humidity climate. So I soap with as little water as I can get away with, use a hot bath for a few minutes until a certain emulsion and light trace, hand stir only, pour into single bar silicone molds (because my bars get rock hard within a few hours, often 6 to 12 hours) and then wrap as soon as they can be released from the mold without getting damaged. I vacuum seal these bars. I know this is unconventional ... but it has worked well for my climate and that brine recipe.

Would be interesting to know your additives and climactic conditions.

 

[PuzzledSoapmaker]

Did you use a hydroscopic ingredient like Dead Sea Salt or Epsom Salt?

Without knowing all details of your recipes (amounts of all ingredients, including additives, oils, water, and lye), it is really hard to even guess what might be happening.

Hi, it is a very basic soap. No additives, no fragrance, no salts. That's why I find the situation strange. I got this recipe from a book and made it a few times already, but never weighed it. The soap itself is great, but the weight gain got me curious. It has 50% olive oil, 22% coconut oil, 14% castor oil, 9% cocoa butter, and 5% shea butter. I made it with a superfat of 15% and a lye concentration of 47%.

I had this issue with my hydroscopic (brine) soap ... that I made in a highly humid tropical rain forest climate. As you can see, I got some weight gains of about 3% when the rains were just beginning by day 17 after pour.

For that brine soap, I do what I call "WARM PROCESS" (neither cold nor hot process). I now have 'WP' in my instructional notes. A key objective is to evaporate away as much water as possible before the soap can gain weight in my highly humidity climate. So I soap with as little water as I can get away with, use a hot bath for a few minutes until a certain emulsion and light trace, hand stir only, pour into single bar silicone molds (because my bars get rock hard within a few hours, often 6 to 12 hours) and then wrap as soon as they can be released from the mold without getting damaged. I vacuum seal these bars. I know this is unconventional ... but it has worked well for my climate and that brine recipe.

Would be interesting to know your additives and climactic conditions.

Hi, that is very interesting. I live in central Europe so my climate is definitely not tropical. We have highs and lows when it comes to humidity though. Lately, it has been between 40% and 90%. I don't know if this matters but - It's been quite dry for a while, and a couple of days ago we had some strong rain - that's when my soap started gaining weight.

My soap doesn't have any additives at all. Just plain oils & lye water.

I'm starting to think that maybe my soap was indeed done curing, and the humidity and rain reversed the process. The question remains - what now?

 

[Mobjack Bay]

Curing and drying are two different things. You can read more about that here. It does sound like your soap is effectively dry relative to the ambient conditions where the soap is curing. Assuming the bars weigh at least 50 g, a 0.2 g weight change is a change of 0.4% or less, which is tiny. When I send soap that is well-cured for months and as dry at it will ever be in humid Virginia (US east coast) to family in very dry Arizona (US west, desert-like climate), the soap shrinks more due to additional water loss. Needless to say, I no longer use cigar band type labels when I send them soap.

 

[ScentimentallyYours]

Right now the natural glycerin in my well cured CP soap is attracting water from the air. It’s been raining here in Massachusetts for the better part of a month. The surface on my CP bars looks like glycerin soap. I want to wrap the bars but can’t because they are so wet. I even have a fan blowing on them now for 24 hours and they are still damp and slimy. Maybe the natural glycerin in our soap isn’t always a good thing?

 

[PuzzledSoapmaker]

Curing and drying are two different things. You can read more about that here. It does sound like your soap is effectively dry relative to the ambient conditions where the soap is curing. Assuming the bars weigh at least 50 g, a 0.2 g weight change is a change of 0.4% or less, which is tiny. When I send soap that is well-cured for months and as dry at it will ever be in humid Virginia (US east coast) to family in very dry Arizona (US west, desert-like climate), the soap shrinks more due to additional water loss. Needless to say, I no longer use cigar band type labels when I send them soap.

My soaps are between 135 - 140g so the change is small indeed. I was just wondering when the moment will come when I will be able to safely package them in kraft paper. I was thinking that it would be as soon as the soaps stop losing weight, but I didn't think they could gain some