I confused 500 ml with 500 g – do I need to throw my first batch?

[alexanderte]

So I think I did a beginner mistake. I bought a 500 ml bottle of extra virgin olive oil from the local grocery store. I didn’t think that 1 ml of olive oil isn’t the same as 1 g of olive oil. Here is the recipe I followed generated by the Bramble Berry Lye Calculator:

Superfat
5%

Lye
63.65 g

Water
165 g

Olive oil
500 g

I read a website stating that 1 litre of a specific olive oil weighs 900 grams. If that’s true in general, then I’ve used around 450 g olive oil for this batch. Hopefully using the wrong amount has “just” increased or decreased the superfat amount – could that have happened?

A few bars that I tested did pass the zap test by the way. So there should be no excess lye left then?

 

[Susie]

If you zap tested, and got no zap, then you have usable soap. No need to panic.

 

[DeeAnna]

Most soap recipe calculators assume the NaOH is 100% pure. That's pretty much never right, so there's a hidden superfat built into every recipe created by such calcs. This hidden superfat is the difference between the assumed 100% pure NaOH and the actual purity of the NaOH you used.

In your case, if your real NaOH is about 95% pure, your real superfat is probably about 3% for the recipe you actually made.

Like Susie said, if it does not zap, it's fine. If you are still worried, let the soap cure for 4-6 weeks. Split a bar open and zap test the center of the bar. If the center has no zap after cure, that is a really super cautious test of safety.