S-7 Development Notes #3 | Same Foam, So Different

← Entry #2: The More I Read, the More Questions I Had

I used to think foam was foam.

To be honest, I barely thought about it at all. As long as it lathered, that was enough. I figured a shampoo lived or died on the “results” — how the hair felt afterward, how it held — and that the foam itself didn’t really have a personality. Right up until I started making my own, I never once questioned that.

Then I started blending it by hand, and that assumption fell apart pretty fast.

The kind of thing only your hands can tell you — and maybe only a hairdresser’s hands

There was a question I’d been carrying since last time. I wanted to really get a feel for the “slip” inside the foam. I’d started to understand, vaguely, that surfactants each have their own character. But what that actually meant, in my hands, I still couldn’t say.

Books didn’t help. Spec sheets didn’t help, no matter how long I stared at them. “Slip,” “that springy, cushiony feel” — none of it turns into numbers. It’s honestly hard to even put into words.

So there was no way around it: I had to check with my own hands, on my own hair.

And once I did, it became obvious. Even the single word “foam” covers so much — dense foam, springy foam, clean foam, heavy-slick foam — and even the way it rinses away under warm water feels different every time. The same white foam, but the way it sits in your hands is completely different.

So how do you actually design it?

So I decided to compare three surfactants, each as close to “on its own” as I could manage. It made me groan a little — this was going to take time — but there was no other way. Let’s call the three foaming agents A, B, and C.

The key here is keeping the conditions even. Match the amounts, and keep one of them in every sample as a shared base. Otherwise you never figure out what’s actually causing the difference.

It’s tedious work. But cut corners here, and you redo everything later. Put another way: get this part right, and you can actually trust the differences you see.

The same foam — so why are they this different?

When I finally lathered them up in my hands, I was genuinely surprised.

A, on its own, already had a beautiful foam. Fine, tight bubbles, great slip. Honestly, I caught myself thinking, “maybe this is all I need.” The hair felt great after rinsing, too. It would need some fine-tuning, sure — but it was clearly going to be a main ingredient.

B was underwhelming on every front — lather, slip, volume. …But there was a distinct “squeak” to the hair afterward, which left me wondering whether its cleansing power might actually be the strongest of the three. And that moderate, clean feeling seemed like it could take a foam that’s too heavy and make it lighter, without giving up the cleansing.

C was the shared base in every sample, quietly holding up the texture of the whole thing from underneath. Just adding it made the foam feel instantly richer.

I’d been lumping all of this under one word: “foam.” But the quality, the slip, the volume — they were this different.

Foam isn’t something you make. It’s something you design.

That realization became the starting point for everything, I think.

“Which foam, combined how.” That’s what making a shampoo actually is — and it finally clicked for me right here. I’d assumed foam was more or less foam. It isn’t. Foam is something you design, precisely.

So before adding anything else, I decided my first goal was to get this foam as close to my ideal as I possibly could. Fragrance, finish — all of that comes later. First, the foam.

At this point, A was still the front-runner

I’ll be honest: back then, I was pretty smitten with A.

The foam, the way the hair felt after washing — both were genuinely good. I was just happy I’d found a great ingredient without much of a struggle. Build around this, I thought, and it’ll surely turn into something good. I didn’t doubt it for a second.

…Well. This A is going to disappear later, in a way I didn’t see coming.

But that’s for another time.

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