Small batches (1-4 oz) - issues with consistency and accuracy?

[RogueRose]

I've made some small batches to try different recipes as I have wanted to try maybe 6-10 variations on a single recipe with different ingredients and such. I've found it is much more difficult to make smaller batches b/c it is more difficult to measure ingredients accurately and I am wondering if these small recipes react the same as a larger batch when it comes to saponification and curing.

Has anyone noticed this and or have suggestions on how to make small batches easier?

 

[MorpheusPA]

You're absolutely going to require a scale that can measure to the gram at absolute minimum, and to the tenth of a gram would be much better. A 1 gram error in 1 oz (28.3 g) is over 3%, which is simply too large an error.

In this case, at a tenth of a gram, you'll want to get close by pouring and then dropper in the rest of the oils. I'd also suggest not using a holding bowl or cup for your oil as even the minor residue of what remains when you pour it into your soap pot will be significant.

I'd suggest a plastic spoon to add the lye to the water as the amounts are going to be extremely small.

I'd go to four ounces minimum, or about 1 full-sized bar (113 grams) if your scale can't do a tenth of a gram. My test size is usually 1/2 to 1 pound, where a 1 gram error is only a quarter to a half of a percent. Even so, subtle differences may show in the final recipe at full size.

Saponification and curing will be identical, although gel phase is going to be extremely difficult to achieve when using smaller recipes. Consequently, if your full-sized recipe gels, saponification will go faster and the final characteristics will be somewhat different. If it doesn't gel, you shouldn't notice a difference.

 

[The Efficacious Gentleman]

I agree with Morpheus that 100g should be the smallest even with a 0.1g measure. I have made 50g batches, but they were really fiddly whereas the 100g was just fiddly!

I do think that in some ways the reaction is different, though. Especially when it comes to heat generated during the saponification or even getting the reaction started. With a smaller batch, you might be best off using a bottle twice as big as the batch (oil size) so for a 100g batch take a 200ml bottle and shake the batter in there to get it to trace.