Monday, 29 August 2011

What is the Gel Stage?

Since posting about the Cinnamon Orange Partial Gel we were asked to explain what exactly  happened for the non-soap savvy readers. So we decided to give you an explanation of the gel stage in the soap making process.

When oil is mixed with lye it goes through what is called saponification. The word literally means “turning into soap”. Oil is a fatty acid and lye is a base, when they combine, they neutralize each other. This is an exothermic (produces heat) chemical reaction where lye and oils combine to make soap and glycerin.

So what is the gel stage? It is part of the saponification process. After mixing the oil and lye and pouring it into a mold, we insulate our molds and place them in a warm dry place, usually the oven (but we don’t turn it on!). The heat produced by the chemical reaction radiates from the center of the soap toward the outside and it starts to look like translucent gelatinous goo…this is the gel stage. Once the process is complete, the whole thing should be completely gelled.  After 24 to 48 hours the saponification process is pretty much finished and we can take it out of the mold.

When we made the Cinnamon Orange Soap, we attempted to stop the gel stage by putting the soap in the fridge. In the picture of the Orange Cinnamon Soap you can see that the center of the bar is gelled and the outer edges are not. For this bar of soap, the gel stage started but since it was in the fridge being cooled down from the outside in, the gel did not reach the outer edges. To completely stop the soap from gelling, it would have to be cooled down faster…perhaps by mixing the oil and lye at a lower temperature and putting it into the freezer.

There is some debate on whether you should let your soap gel or not. Some soapers do and some don’t. Skipping the gel stage does not mean that the oils are not fully saponified at the end of the process; it just means that the process takes longer and the bars need more time to cure. The Orange Cinnamon soap was our first attempt at preventing the gel stage so we can’t really speak to the quality of gelled versus non-gelled but you can see the difference in color in the Orange Cinnamon Soap. The outer edges are a brighter more yellow-orange color and the center is darker.

For pictures, take a look at my previous post called “Cinnamon Orange Partial Gel” or take a look at the information on Ask Anne-Marie about the gel stage Ask Anne-Marie Part2 | Soap Making FAQ | Teach Soap

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