Soda: The Story of an Oven with a Happy Ending

As you may already know, to make soap you need oil and lye. Oil is pretty much the same. But what about lye, sodium hydroxide, or NaOH for short?

What is it? Where can we find it? How does it grow?

Originally, soda was obtained by burning seaweed. Yes, that black, dry seaweed that stings your feet on the beach.

You can still see the old soda kilns along the Breton coast. Nothing spectacular, they look like small stone trenches, but for centuries, they were the livelihood of many seaweed harvesters.
People on the verge of poverty, let's be clear. It was hard, physical work, and very poorly paid. It took an incredible amount of seaweed to obtain a tiny quantity of soda, which was mainly used to make iodine tincture at the turn of the 20th century, when asepsis demonstrated its value in preventing infections.

But while medicine was progressing, the coasts of Finistère and the island of Molène were disappearing under a cloud of suffocating pollution.

On paper, burning seaweed may seem like a natural, simple and ecological method, but when you look more closely, it's not so appealing.

Then came industrialization and progress in synthesizing soda.

And we went through some not-so-nice stages, with techniques involving mercury, for example. Without going into detail, we're glad it was just one stage.

Today, the technology has become simple and clean: electrolysis of salt water with passage through a system of membranes that sort the NaOH molecules.

So no, soda is not a natural product, you don't find it as is while walking on the beach, but to make good soaps, it is essential and its production has made enormous progress over the last century.

Plus, you can find it in France, which doesn't take anything away.

And I want to pay tribute and homage to all those who, on the beaches of Brittany, wore themselves out for almost nothing a hundred years ago. Your work is precious to me; it had to start somewhere.

Solène Lebon