Undissolved Lye

[Gardengirl7]

Will rebatching cold process soap with undissolved lye fix the problem and make the bars usable or do I have to throw away the whole batch?

 

[ResolvableOwl]

It might. Sorry to hear . I guess you'll join the team “pour lye solution into oils through a strainer”. Another issue with lye crystals/pockets is that the lye is missing in the main batter, hence one has unplanned excessive superfat with all its downsides.

Back to rebatching: The point is, it depends on the recipe, water content, and age of the soap if rebatching is able to completely dissolve the solid structure that has already built up during the first hours/days of CP curing. Even if you grate it up finely (cheese/garlic grater), the “noodles” might not fully dissolve in the extra rebatch water, and can keep small lye pockets enclosed – defeating the whole reason for rebatching.
If your recipe is well-behaved/soft enough (and your soap young enough) that it will turn into a liquid-ish paste state when hot, then you can stir it thoroughly.

In any case, wrap it so that it loses as little moisture to evaporation as possible. Once you're ready, grate it up as finely as possible. Wear gloves and goggles. The least painful rebatch method is oven rebatch.

Keep us updated how it goes!


I guess you have made the zap test to be sure it's lye. ETA: Can you post pics? Lye crystals/pockets have turned out more than once to actually be incompletely mixed FO, stearic spots, air bubbles, or exaggerated damage from wire cutters.

 

[TheGecko]

Maybe...maybe not. Speaking solely for myself, I don't mess around with lye. If I screw up, I take the loss rather than potentially endanger my customer, friends or family. But it's up to you...you can try it...grate it up, add water, melt, stick it back in a mold and then zap test it.

 

[DeeAnna]

Do you absolutely KNOW there is undissolved lye in the soap? I'm not saying it does not happen because it does on rare occasions, but it's truly rather difficult to create this problem.

Based on what I see on this forum, it's far more common for soap makers to leap to the conclusion their soap has undissolved lye when it's actually something more benign like heavy ash, spots of colorant, stearic spots, "glycerin" rivers, or whatever.

 

[Cat&Oak]

I personally would not mess around with that and would toss the batch.

 

[Gardengirl7]

Thanks so much for the information. I had already tried rebatching it but unsure about the soap, I really don't want anyone to get burned.
I got a good strainer which I will use from now on. On the zap test, does that mean when you test one bar from the batch that will tell you the whole batch is lye heavy or not?

 

[ResolvableOwl]

On the zap test, does that mean when you test one bar from the batch that will tell you the whole batch is lye heavy or not?

If you test one bar and it is zappy, then expect all to be unusable. If you test one bar and it is not zappy, this is no guarantee that all are fine. Not even the one you tested, if you fear undissolved/unreacted lye. Sorry.

 

[Gardengirl7]

Thanks so much for the information. Have been learning lots. Going to make soap tomorrow and will be extra careful.

 

[Johnez]

If you test one bar and it is zappy, then expect all to be unusable. If you test one bar and it is not zappy, this is no guarantee that all are fine. Not even the one you tested, if you fear undissolved/unreacted lye. Sorry.

This. The problem here is as RO pointed out earlier, undissolved lye creates unintended superfat. This will result in a possibly non-zappy, but still problematic batch if you have pockets of lye trapped.

The question that needs to be answered is are you really sure there is undissolved lye? What are you basing this off? I can't see how rebatching would address undissolved lye unless you literally turned the soap into powder.

 

[HoliHealerz]

It might. Sorry to hear . I guess you'll join the team “pour lye solution into oils through a strainer”. Another issue with lye crystals/pockets is that the lye is missing in the main batter, hence one has unplanned excessive superfat with all its downsides.

Back to rebatching: The point is, it depends on the recipe, water content, and age of the soap if rebatching is able to completely dissolve the solid structure that has already built up during the first hours/days of CP curing. Even if you grate it up finely (cheese/garlic grater), the “noodles” might not fully dissolve in the extra rebatch water, and can keep small lye pockets enclosed – defeating the whole reason for rebatching.
If your recipe is well-behaved/soft enough (and your soap young enough) that it will turn into a liquid-ish paste state when hot, then you can stir it thoroughly.

In any case, wrap it so that it loses as little moisture to evaporation as possible. Once you're ready, grate it up as finely as possible. Wear gloves and goggles. The least painful rebatch method is oven rebatch.

Keep us updated how it goes!


I guess you have made the zap test to be sure it's lye. ETA: Can you post pics? Lye crystals/pockets have turned out more than once to actually be incompletely mixed FO, stearic spots, air bubbles, or exaggerated damage from wire cutters.

Thank you. Now I know that what I thought happened to me today - did happen. 🖐guilty. First fail.
It happened because I poured infused sumac seed water into the lye and when I wanted to strain the bits before pouring into the fat, I thought maybe it was sumac seeds plus my strainer was full of seeds. Then the hot process didnt work and so I just poured and put it into the freezer for come what may. What may, came. I have a lump of hard fat. Fortunately it was a test quantity so not much ventured and little lost but I will try to salvage with the advice you gave. For the sake of science.
Thanks again. Useful.
I also almost poured the water into the lye. Yes - distracted.