Why I Put Citric Acid in My Dish Soap Block Formulation (most formulas leave it out!)

If you’ve made the switch to a solid dish soap block, you already know the benefits : no plastic, lasts for months. But if you've ever stumbled across a bar that left... residue (eww) - that's a formulation issue.

It's all about this one little ingredient called : citric acid.

What is citric acid?

Citric acid is a naturally occurring acid found in citrus fruits. In cleaning formulations it acts as a "chelating agent", which is a fancy way of saying it binds to minerals in hard water and stops them from reacting with your soap.

Why does that matter?

Tap water has minerals and hard water especially is full of calcium and magnesium ions. When those minerals hit a soap bar, they react and form soap scum - that white filmy residue that ends up on your dishes, your sink, and your soap itself. It's chemistry gone wild.

Citric acid intercepts that reaction. It grabs onto the minerals before they can start soap scumming (that should be the technical term!), which means your dishes rinse cleaner, your sink stays cleaner, and your bar lasts longer.

So why doesn’t every dish soap block have it?

It really should be! It truly makes a difference in the quality of clean you can get from your soap bar. It is an extra ingredient, and a bit more complex to work with.

We’re a small batch formulation-first operation though. Every ingredient earns its place. And citric acid really does earn a spot in a dish soap bar.

The short version

Soap scum is hard water minerals reacting with soap. Citric acid stops that reaction before it starts. Your dishes are cleaner and your sink will be thanking you.

You’ll find citric acid in both scents of our solid dish soap block : Lemon, and Orange Tangerine. Available as a single bar or in a starter kit with a Canadian pine soap tray and bamboo brush.

A note from the formulator :

Citric acid is one of those ingredients that is a great addition but you have to work a little harder to make sure your calculations are spot on in bar soap. The citric acid will react with the lye during saponification, so you have to adjust your lye calculation to account for it, otherwise your bar will have too much unreacted (superfat) oils and can make a greasier/soap scum-prone bar. I formulate this bar to 0% superfat, which means every gram of citric acid gets accounted for, there’s no extra fats being left on dishes, and the bar is truly effective.