Making the lye solution

Sixty seconds of real hazard in an otherwise gentle craft, and it is entirely manageable with a routine.

The one genuinely hazardous step

Goggles on before the container is opened. Gloves. Long sleeves. Closed shoes.

Ventilation: a window open, an extractor on, or do it outside.

Nobody else in the room, no pets, no children, and nothing else happening at the same time.

A heat-resistant container that is not aluminum, because lye attacks aluminum and produces hydrogen.

Lye into water

Always, and never the reverse.

Adding water to solid lye can cause a violent eruption, because the heat is generated faster than the small volume of water can absorb it.

Lye into water, slowly, stirring as it goes.

This is the single rule in the craft that has no exceptions and it is worth saying out loud every time, because familiarity is what erodes it.

What happens

The solution heats rapidly, to around 90 degrees or more, within seconds.

It gives off fumes for the first minute or two which should not be breathed: turn your head away, and do it where the air moves.

It goes cloudy and then clear.

Stir until fully dissolved, and check the bottom of the container, because undissolved lye sitting there is a lye pocket waiting to happen.

Cooling and holding

Let it cool to the working temperature, which takes a while and is usually the longest wait in the process.

A water bath speeds it up safely.

Label the container, unmistakably, if it is going to stand. A jug of clear liquid on a bench is exactly what somebody will pick up.

And if the recipe uses milk or another sugar-bearing liquid, the whole procedure changes: freeze it, add the lye slowly to the slush, and keep it cold, because the sugars will scorch.

References