23th Nov 2013 shall henceforth be officially known as the day when The Soap Engineers becomes THE Soap Engineers.
The afternoon started normally. It was windy and really chilly, but that did not stop Puja and Brooke from making their way down to my house. The week leading up to this date was filled with research, reading up, planning and lots of supply shopping, and accompanying all these activities was an undercurrent buzz of excitement.
This is it! We are either going to blow up the kitchen, or we will have made soap!
OUR PLAN – Being nubes, our plan was to make a sample bar of soap from each acid group just so that we will have a first hand feel and comparison of each group’s properties.
This was our original list of single oil soap we planned to make.
- Oleic acid – Olive Oil
- Lauric acid –Coconut Oil
- Palmitic – Palm Oil
- Ricinoleic – Castor Oil
- Linoleic/Linolenic – No intention of testing since we know it won’t set up.
Excitement buzzing, we put on our goggles, pull on our gloves, snap on our masks and prepare to measure and melt the oils.
Then we promptly hit a snag, which grinded our golden plan to a halt.
THE SNAG – I have a nice electronic scale which I generously contributed to the noble cause of soap making. While my dear scale is more than adequate for chocolate muffins and pound cake, it is nowhere near useful as a makeshift scientific weighing scale. The readability of my scale is 1 g, or 0.1oz. To make a single bar of sample soap means that we need to go down to a minimum of 2 significant figures in order to accurately measure out lyes and oils. Apart from the lack of significant figures, my “trusty” scale started to act all funny when it found out that it will be relegated to measuring lyes and oils for the rest of its life. The reading panel starts fluctuating by itself with or without anything on the scale. I walked past it, it shows 0.5 oz. Puja clapped, it flipped back to 0 oz. Brooke sneezed, it switches to 0.2oz. I swear, if it wasn’t for the fact that it was bright daylight, we probably would have freaked out.
So, since my scale’s readability and dependability is woefully inadequate, we had to rethink our strategy.
THE IMPROMPTU NEW PLAN – So here we are, masks gloves and goggles on, we quickly formulated Plan B – to create a larger sample bar of a mixed oils. Instead of testing the soap properties, we’ll test out color and scent combination. If we are lucky, we may even get to try our hand on some artistic swirls. With that amount of oils, the lye required could be effectively measured in 1 significant figure, allowing us to use our only available scale.
Engineers are really practical people, and we developed a really great life philosophy – “When life throws random lemons at you, you just got to get whacked in the face, pick up the lemons and attempt to make lemon soap with it.” Hey free lemons, can’t complain.
PLAN B – Here’s the final plan involving all four of our original test groups – Lauric, oleic, palmitic and ricinoleic. We’ve also decided to superfat our blend by the seemingly magical number of 5% to make sure we are able to compensate for any existing fatty acid variation that could occur due to different material sources, geographical location, processing etc. Once of these days, we will experiment with the effects of varying superfat percentages. I, for one, am super curious to see the impact of different superfatting percentages. Life, apart from throwing lemons and laughing at you, can sometimes feel bad, and award you with happy accidents instead. The usual palm oil was out of stock, so we picked up an organic red palm oil as a replacement. The oil was really red when we first melted it, but, this rich color eventually transformed into a delicious, creamy, orangey yellow base at trace. It was simply stunning to look at and resembles very much like a mango smoothie.
Because we originally set out to only make super tiny test batch, we did not see the need to purchase any handheld blenders. Now that we are forced to make a larger batch, we had to make do with a good old fashion whisk. We each took turns whisking, testing essential oil blends, and topping up and sipping wine. 15 mins into whisking, we did it- we achieved trace! That moment was one of those golden moments where we dropped everything, crowd round the bowl and admired the effects.
Since the base color was already a nice golden shade of yellow, we decided to incorporate citrus scent into our soap.
Here’s us doing our oil blending work – this involves lots of sniffing, keeping track of which caps belongs to which essential oils, and jotting down what we think might make a great scent combination.
To run our scent and color split, we divided the soap base into four “equal” parts. Equal is in quotation marks because after glasses of chardonnay, the word “equal” simply doesn’t exist. Lesson learned – if wine is involved, measuring cup is a must.
Here is our final scent and color split table.
A couple of things we want to find out:
- Is the scent(s) able to withstand the subsequent oven processing we will be subjecting our test batch to? And to what degree?
- Is there any particular oil that will accelerate trace?
- Is there any particular mica/oxide will transform during, and after saponification?
- What is the scent of our original soap base?
THE OVEN DISASTER – Because we simply couldn’t tolerate the thought of waiting 6 weeks before we are able to test our soap, we opted to accelerate our saponification process and cure time by applying the cold process oven process (CPOP). The supplied heat, we postulate, will increase rate of saponification, induce gel phase and help evaporate excess water in our soap mixture. This should cut our curing time down to a mere week.
And this is the one step that went horribly wrong. We know that heat is good, but, we did not realize that there is such a thing call too much heat. We left our test bar in the oven at 170 deg for 2.5hrs thinking that longer cook time is better. We found out later that the residual heat from pre-heating the oven is more than enough to induce gel phase and complete the saponification process. Not to mention that for small test bars like ours (5” x 3” x 1”), it probably would have completed gel phase within 20 mins with a pre-heated oven and heat off. Instead, we “overcooked” our soap, and the result of that was rough, blistery looking top and edges.
THE SNIFF TEST- After 24 hours, when we unmold our soaps, we did a sniff test. Predictably, a lot of our scent was cooked off. Monitoring the smell over the course of the cure, we uncovered even more characteristics of how the scent changes. The below table documents our observations:
- Our soap base smells nice even without any scents added.
- Adding fragrance and essential oils can be a very interesting experience. We added a couple of EOs and FOs, and the addition of each changes the properties of the soap. Most were ok, didn’t observe much negative impact. The addition of rosehip & sandalwood however accelerates trace. We still need more data to decouple which oil is actually the culprit. If you already know which one does, please comment. It would save us some time.
- Sandalwood also happens to be a really subtle scent (read: disappearing scent) which completely disappears into the oil/lye blend no matter how much we put in. Eventually, we had to add in some rose fragrance to bump up the fragrance. We need to look into sandal FO instead of relying of EO. Sandalwood also cooks off really quick. By day three, I can detect no sandalwood scent in both our CPOP and CP samples.
- Rose Fragrance oil is the one that surprised me. I cannot find any flashpoint information on it, but I fully expect that the fragrance will remain even after hot process based on my experience with it for bath bombs and sugar scrubs. It seems that I was wrong. By day three, the rose fragrance was really faint in our CPOP soap samples. CP sample still rocks though.
- Peppermint is strong. It takes far less peppermint oil to scent the entire batch then our other oils. Although CPOP cooks off a fair amount of peppermint smell the peppermint scent is still acceptable.
- Comparing across all samples, generally CP soaps retains scent very well even after day three. Today, as I am writing, the CP samples (Our control group) is still doing very well as compared to its overcooked counterpart.
- As a side note – I couldn’t help but wonder, if we did not overcook our CPOP samples, would the results be different? It would be interesting to characterize the relationship between Time and Temperature and resulting Strength of Scent and Staying Power. This is worth a study.
- We read that TiO2 turn soap white. But we found out that technically, TiO2 doesn’t turn things white. TiO2 is a crystal with very high refractive index which is similar to that of diamond. When it is mixed in any soap base, the crystals gets dispersed throughout the base, and refracts any light that happens to shine through it. Therefore, when our base is orangey yellow, it made perfect sense that it will turn opaque yellow due to the refraction of light. Following the same line of logic, if our soap base is white, or cream, addition of TiO2 will indeed help in in “whitening” the base.
- Cellini Red turns original soap base from orangey yellow to a deep rich red. But this red oxidized to a dull brown upon curing. This effect is apparent during initial cut – the borders of the soap were dull brown, the center was bright red. Within 30 mins, the center turns dull brown, and is now homogeneous with the edges.
- Summer Paradise Tan was initially a beautiful shimmery bronze mica. While the swirls we made still shows the shimmery effect, we did not observe any shimmer effect in both CPOP/CP soap samples after we cut it. To get shimmer, we might have to try glitter instead.
- The original soap base with no color added cured to be a gorgeous creamy yellow soap. We just accidentally found a natural way to make yellow soaps.
This Sat is the day when we will first test for alkalinity. If it passes, we will definitely test the actual feel of the oil blend.
As far as first try goes, we think we did pretty good! And the kitchen is still intact.
Although, we must admit, we almost did blow up the kitchen, and luckily Puja saved the day! So ladies and gentlemen – LYE IN THE WATER! NOT THE OTHER WAY ROUND!!!
Anyway, if you made it this far down, thanks for the patience! I admit this is a super long post, but hey, it sure was an exciting day for us.
Anyway, we would like to wish you and your family a very happy Thanksgiving! Have fun! Eat more! Drive safe! And may you score all the deals you want on Black Friday! 🙂
As for my turkey, I might receive comments on how it has a unique taste of citrus, peppermint and a touch of rose and sandalwood. I will need to think of a good way to dodge that topic if it comes up.