Sterilize all of your equipment by running it through the dishwasher. Wash your hands thoroughly, and consider wearing disposable gloves while making the lotion. Microbes that are on your hands and equipment can make their way into your lotion and spoil it.
Measure the ingredients of the oil phase into one heat-proof glass jar. Measure the distilled water amount for the water phase in a second jar. Next, place both the jars in a large saucepan, and fill the pan with an inch of hot water.
Bring the water to a boil, and reduce the heat to a simmer. You’re ready for the next step after you’ve heated and held the jars for at least twenty minutes, and the contents of both jars are 75°C/165°F. Take the jars out, and place them on a kitchen towel on the counter.
Next, pour the heated distilled water into the oil-phase jar. You’ll see it immediately turn an opaque creamy color. Gently stir with a spoon for several minutes, then let it cool. Leave the spoon inside the jar since you’ll need to return five minutes later to give it another stir.
As the lotion cools, it will thicken to a cream consistency. Return every twenty minutes or so to gently stir. You can also add the Geogard Ultra at this point.
If you make this lotion without a preservative, it will last up to one week in the refrigerator. After that time, invisible bacteria and fungi will begin colonizing it and it will not be something you want to put on your skin.
To preserve it for longer, you will need to add a broad-spectrum preservative. There are many available but my favorite is Geogard Ultra. It comes in a powder form and you’ll need to dissolve it in a teaspoon of hot water before you add it to your lotion. Geogard isn’t heat-sensitive so you can add it without taking the lotion’s temperature. It will preserve your lotion for eighteen months.
Many other broad-spectrum preservatives need adding at precise amounts and temperatures. If you choose another type, please refer to the manufacturer’s instructions.
If you’d like to add the optional essential oil, stir it in when the lotion is 45°C/110°F or cooler.
Now we need to test for pH. Stir a half teaspoon of lotion in 1-2 tsp distilled water. Dip one of your pH papers into liquid and then compare the color to the ones on the pack. Lotion and skin creams need to match the pH of your skin or they can be irritating and affect the effectivity of preservatives. If the pH is between 4.5-5.5 you’re spot on.
You can make the lotion more acidic (lower the pH) up by adding tiny amounts of lactic acid or citric acid dissolved in a small amount of warm, distilled water. Make it more alkaline (increase the pH) with triethanolamine or by dissolving a small amount of L-Arginine or bicarbonate (baking soda) in water and adding it. Pass it through the sieve and into the lotion. Take the pH reading again and adjust again if needed.