Learning to formulate: The water phase

As we know, there are generally three phases to our lotion - the heated water phase, the heated oil phase, and the cool down phase. Let's take a closer look at the water phase.

The heated water phase consists of water soluble ingredients that can safely be heated and held at 70˚C for 20 minutes. This includes water, hydrosols, aloe vera, hydrolyzed proteins, humectants, and some cationic polymers. The amount of water you include in lotion is key to the thickness of the final product. More water equals a thinner lotion; less water equals a thicker lotion (for the most part). 

As I mentioned yesterday, I consider a basic lotion to contain about 70% water, but we don't have to use all water for that phase. We can include water soluble ingredients that are liquidy like aloe vera and hydrosols, or we could include water soluble powdered ingredients like powdered forms of panthenol or sodium lactate or allantoin. 

So how to figure out when to include your water soluble ingredients? If your ingredient can tolerate heat, then add it to the heated water phase. If your ingredient won't tolerate heat, then add it to the cool down phase. (Click on the link for more detail.) Most of our humectants - glycerin, sodium lactate, sodium PCA - tolerate heat, but some don't, so check before using. Something like panthenol doesn't tolerate heat well, so add that to the cool down phase. Allantoin can be used in either phase, so choose the method you find produces the fewest shards. Some of our cationic polymers - like polyquat 44, polyquat 7, and polyquat 10 - like the heat, whereas honeyquat will give off an unpleasant scent when heated. (I try to include this information in every ingredient post, which you'll find to the left of the blog under "bath & body guides to ingredients" or in the "links to lists" section.)

As we work through this formulating series, keep in mind that we're working with percentages and every recipe should total 100% in the end. So when I'm talking about increasing the oil phase, I'm talking about increasing the percentage the oil phase takes up in a recipe. When I'm talking about decreasing the water phase, I'm talking about the percentage the water phase takes up in a recipe. For a recipe like my sample one, I'm using a 69.5% water phase and a 29% oil phase with 1.5% in the cool down phase for a total of 100%. If I increase one phase, I have to decrease the others to maintain that 100%. 

Finally, you'll notice that when I increase my oil phase I tend to decrease the water phase. This is so I can compensate for the increase in oil soluble ingredients and emulsifiers so the lotion is stable. So the water phase is more variable than the oil phase. But remember that if you decrease your water phase, you will make a thicker product. 

So let's take a look at the oil phase!