Sanitize all pieces of equipment (jars and whisk or detachable immersion blade) using hot water and soap or the dishwasher. Disinfect your workspace and wipe down with a clean cloth.

Using a kitchen scale, measure 65 grams of distilled water (or preferred liquid) into a sanitized jar. In another jar, measure out 30 grams of oil. Add 4 grams of emulsifying wax, unless the label specifies adding it at a different time in the process.

Transfer the jars into a wide-bottomed, large pot or Dutch oven. To make a water bath, fill the pot with 2-3 inches of water. 

Bring the water to a steady simmer and then turn the heat down so that the water is barely simmering. Gradually bring the temperature of the water and oil up so that it sits around 160°-170°F/70°-75°C.

Before combining the ingredients, measure the temperature of both the water and the oil—they should be roughly the same temperature.

Carefully pour the hot water into the hot oil. Use a whisk or immersion blender to blend the ingredients until emulsified, and the mixture has begun to thicken and turn opaque.

Allow the lotion to cool until it reaches 85°F/30°C. As the mixture cools, measure its pH using paper pH strips. If the pH is on the high side, add about 3 drops of lactic acid. If the pH is low, add a tiny pinch of baking soda. If you’ve made any adjustments here, blend the lotion again. You can also add your choice of essential oils at this stage.

Carefully decant the cooled lotion into silicone tubes or small glass jars with lids.

As long as a broad-spectrum preservative was used, your lotion should keep for up to 3 months. Store lotion in the refrigerator for even longer or if you choose not to include a broad-spectrum preservative in your formulation.