Weight measurement versus Cup measurement

by Judith

I am new at soap making and don't have a weighing scale yet. I usually draft down my different recipes then use the weighing scale at my place of work to weigh my lye but use cup measurement for my oils at home.

I just came across one of the comments saying "all measurement should be weight measurement not volume."

Does it have a significant difference when using volume measurement? I really want to know.

I have prepared three small batches of soap (310g) and wondered if they could be lye heavy?

I started using one of the soaps and am kind of experiencing dryness and sometimes itchiness.

Could it be the soap?


Using weight measurement is very important when it comes to soap making.

One cup of coconut oil is the same size as one cup of sweet almond oil but it is not the same weight. And this is why it is so important to use weight measurements.

The amount of lye you need in your recipe is calculated on the weight of the oil and not the fluid ounces so it is quite possible that your soap could be lye heavy. Especially since you are making very small batches of soap.

The smaller the batch of soap you make, the more accurate your measuring needs to be. There just isn't any room in your super-fat to cover mistakes.

As soon as you are able, I suggest investing in a soap scale. Thankfully, there are very economical ones on the market these days! In the mean time, see if your employer will let you weigh out your oils as well on your work scale.

The dryness and itch could be from either the soap being a bit lye heavy or you could be reacting to one of the ingredients you are using.

Some people are sensitive to different carrier oils and essential oils. To test if you are having a reaction to a carrier oil, rub a small amount of the oil into the inside of your elbow (soft, sensitive spot) and leave it for 24 hours. If you start to experience any redness and itching in the area during that time, you are likely sensitive to the oil. Wash the oil off immediately.

To test essential oils, you will first have to dilute it considerably in a carrier oil that you are sure you are not sensitive to. Then proceed as with the carrier oil test.

Good luck,

Comments for Weight measurement versus Cup measurement

Average Rating starstarstarstarstar

Click here to add your own comments

Measuring Soap Ingredients
by: Cathy

I would certainly try using the soap for laundry or even dishes. Just be sure to rinse and use gloves to protect your hands, especially since you experienced dryness and itching.

A kitchen scale is perfectly fine as long as it is accurate and can weigh in grams. You do not need to purchase one made specifically for soap making...I sure didn't!

8.5 is a good pH for soap and it may not be lye heavy if that reading is accurate. Maybe have a friend test your soap out as well...on the hands only as they tend to be less sensitive. Be sure to do the skin tests with your ingredients before you make your next batch. Coconut oil and cocoa butter are ones that tend to be sensitizing.

Good luck!

by: Anonymous

Thanks so much for the information, it was really helpful.
I also forgot to mention that the pH of my soap was 8.5. That is okay for use right?

I am not sure I can get a soap scale in my locality, cos I haven't met anyone who is into making solid soaps. Liquid soaps are what is common and the ingredients are sold already weighed.

Can I make use of a kitchen scale?

For the batches of soap I made what should I do with them? Can the be recycled into something else, as laundry soaps?or detergents? Or am to discard them.

Will try increasing my batch size, maybe up to a pound for next production.

Click here to add your own comments

Return to Submit a Question.

Like This Page?