Soap Making for Beginners: 10 Common Mistakes
Making soap can be exciting, but to be honest, there is definitely a learning curve. I frequently tell people that making soap is not hard - the hard part is knowing when something is not correct or what to do to fix it. Starting your soap making journey is exciting—but there’s definitely a learning curve. Soap makers rarely fail because soaping is too hard, but there are a few mistakes that can cause big problems.
If you want better batches, less frustration, and more confidence, this guide may save you a lot of trial and error.
Mistake #1: Not Using a Lye Calculator
This is the biggest one and it is one I see frequently. I see soap makers say they found a recipe online or got one from AI and even a quick look tells me that the numbers are not right. I encourage you to experiment with different oils and recipes, but please be sure to run all of them through a lye calculator prior to making.
Soap making is a chemical reaction, and every oil requires a specific amount of lye to properly saponify.
If you don’t calculate correctly, your soap can be:
- Too harsh (lye-heavy)
- Too soft or oily
Fix:
Always run your recipe through a reliable lye calculator—even if you’re following a recipe.
Mistake #2: Measuring by Volume Instead of Weight
Cups and tablespoons do not belong in cold process soap making. If you find a recipe that gives you measurements in volume instead of weight, please be sure run it through a lye calculator. You can absolutely use those volume measurements to calculate the percentages used and use those percentages to determine your weights needed.
Different oils have different densities, so volume measurements are inaccurate and inconsistent.
Fix:
Use a digital scale and measure everything in grams for precision.
Mistake #3: Using Too Much Coconut Oil
Coconut oil gives amazing bubbles—but it’s also very cleansing.
Too much can strip the skin and leave your soap feeling harsh. Yes, you may see some 100% coconut oil soaps out there, but if you research the recipes, they need to be superfatted at 20%+ not to be too drying. I have also seen reviews that say the soap is somehow too drying for their skin while also being greasy.
Fix:
Keep coconut oil around 15–30% of your recipe for a balanced bar.
Mistake #4: Skipping Safety Precautions
Lye is safe when handled correctly—but it does require respect. You absolutely need to make sure you have proper ventilation when mixing lye with your liquid. The chemical reaction gives off heat and some very nasty fumes.
Skipping gloves or eye protection is another risk you don’t want to take.
Fix:
Always use:
- Gloves
- Eye protection
- Proper ventilation
Mistake #5: Soaping at the Wrong Temperature
Temperature affects how your soap batter behaves. As you gain more experience, it can be fun play around soaping at lower temperatures, but until you have a good feel for trace, I recommend keeping a close eye on temperatures. You also have to get a good feel for how any additives will impact the temperature of your soap as well as how some fragrances impact the soap. Some fragrances will accelerate your trace while others can slow things down. If you soap hot with a fragrance that accelerates, you may not even be able to get your soap out of the pot.
Too hot → fast trace, possible cracking
Too cool → false trace or separation
Fix:
Aim for a general range of 90–110°F for both oils and lye solution (flexible, but a good starting point).
Mistake #6: Not Understanding Trace
Trace is when your soap batter thickens enough that oils and lye are properly emulsified. Trace is very hard to describe, but once you have a couple of batches under your belt, it will be much easier to know when your soap starts tracing. I usually look for slight thickening of the batter and when I let drops fall on top, they leave a mark, but easily stir down. Once I get to this point, I know I can divide if needed for color or if I am doing an in the pot swirl, I may mix just a little more.
Beginners often:
- Stop too early → separation
- Go too far → thick, hard-to-pour batter
Fix:
Look for a light to medium trace—like thin pudding—especially when starting out.
Mistake #7: Using Too Many Oils in One Recipe
It’s tempting to use everything you have—but more oils doesn’t equal better soap. Simpler is better for starting and then change 1 or 2 things at a time. Personally, when I was developing my favorite recipe, I would only make one change at a time so I was able to know exactly how my change impacted my soap.
Too many variables make it harder to:
- Predict results
- Troubleshoot problems
Fix:
Stick to 3–5 oils until you understand how each one behaves.
Mistake #8: Not Letting Soap Cure Long Enough
Just because your soap is hard doesn’t mean it’s ready. We cure ours at least 4 weeks and some batches get even longer. A longer cure gives you a better bar and can fix a lot of problems. Technically, most of the saponification process is complete in the first few days, but your bar will benefit significantly from a longer cure. We weigh bars from each batch to track evaporation so we can know when most of the water weight is gone and when they are ready to start labelling.
Curing allows water to evaporate and improves:
- Hardness
- Lather
- Mildness
Fix:
Cure your soap for at least 4–6 weeks in a dry, ventilated space.
Mistake #9: Adding Fragrance Without Testing
Most fragrance oil suppliers will give you notes on how a fragrance behaves, and honestly, if they don't have this information available, I would not purchase. You want to know that they have also done testing on their end to make sure that a fragrance is suitable for soap. I have been a part of some supplier testing while some fragrances are soap safe, they caused so many problems that they were not usable.
One quick tip on fragrances, regardless of what the supplier notes say, I always assume that anything with floral or spice notes is going to cause some kind of acceleration with my soap. I will make sure to soap these a little cooler and try to keep my colors to just one or none depending on how I think they will behave.
Some fragrance oils behave badly—they can do any or all of the following:
- Accelerate trace
- Cause seizing
- Discolor your soap
Fix:
- Check supplier notes
- Start with small batches
- Be ready to work quickly
Mistake #10: Not Keeping Notes
This one seems small—but it’s a game changer. I keep a batch page on EVERY batch of soap I make and have binders full of all my batches. Over the years, I've made my own batch list that has recipe info, additives, fragrance info, a spot for notes as well as a weight tracker. After I make a batch, I take a minute and make any notes. Sometimes this may just be "great pour" or I have one that just has ACCELERATED scribbled on the bottom, but I always take that minute to make notes because you will not remember later. I usually make 5 batches at a time so I take that little bit of time in between each to make sure that I've made some kind of note for each batch.
If you don’t write things down, you won’t remember:
- What worked
- What didn’t
- How to fix it next time
Fix:
Keep a simple soap journal with:
- Recipe percentages
- Additives
- Observations