Have you ever searched the internet for cosmetic formulas? A search turns up more variations than you can try in a year, perhaps more. The question is, of course, are they good? Will they provide the results you hope for? Are they well researched and written? Unfortunately, an alarming number call for measured ingredients, in cups and tablespoons.
What’s wrong with that?
Is it acceptable to measure in cups and tablespoons? Must I own a scale to make good products? This is particularly a dilemma for those used to cooking and baking with measuring cups and spoons, rather than by weight. It is only natural for someone new to cosmetics to choose formulas that employ measuring utensils similar to what they use in their kitchens. And yes, I know. Many of you think of your first soap formula that you successfully produced or your great grandma’s formula calling for a can of lye, the fat from a hog, cups of this and spoons of that.
Yes, you and others create or created outstanding batches despite imprecise tools and methods. It has worked so far and you are satisfied.
What is the problem, then?
The problem is, a “recipe” in cups and spoons does not provide precision and consistency. If you get a new measuring cup or share the formula, for instance, the result may not be as favorable or consistent. This is because measuring utensils are approximate. What measures cup to you might be less or more for someone else, which can throw the product off enough to cause a failed batch; the smaller the batch, the more likely this is to occur. To test the theory, measure water to fill a one cup measuring cup and pour that into another one cup measuring cup. If you have several, try them all. You will probably find that the amounts vary. The same is true with measuring spoons.
In addition, the measuring cups are not meant for liquids, so measuring oil in a one cup measure meant for dry ingredients does not offer the same result as a cup meant for measuring liquid ingredients. If we cheat a bit in cooking, it doesn’t usually matter, but in cosmetics and soap, it can make a big difference.
Consistency and accuracy are important in making repeat batches, especially for sale, so the best way to ensure consistency is by weighing ingredients rather than measuring them.
At one time, accurate measuring tools were hard to obtain, but this is the 21st century; a good digital scale is a store or internet order away and inexpensive for most of us. Best practice, even for hobbyists, is to measure by weight.
What Should I do?
Purchase a digital scale. Fortunately, what you need is not terribly expensive. The least expensive run on batteries, but calibrate them often because when batteries begin to lose power, the weight fluctuates, causing wildly inaccurate measurements.
A scale that comes with an adapter so you can plug it in is even better to avoid worries with weakening batteries. Calibrate it on a regular basis, anyway, but deviations due to low batteries are non-existent, and you avoid constantly buying those pesky batteries. Calibration weights are very helpful, and recommended, as well.
Look for a scale that measures in grams as well as pounds and ounces if you are in the USA. This is a good way to get used to working in grams. They offer more accuracy and simpler conversions, overall. If you plan on making large or tiny batches, you will probably need to invest in a second scale or even more. To begin with however, a scale that weighs as small as a gram and as high as ten pounds or so, is suitable for soap and medium batches of lotion and such.
Cups and spoons are not acceptable for soap or cosmetics. When precision is imperative, weigh. When consistent batches are necessary, weigh. Your scale is sure to become your new best friend!
What weighing tips do you have?
Until next time, may your days be filled with bubbles and wax.
Beth Byrne, for Making Soap, Cosmetics & Candles Magazine