What lye concentration do you use?

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Well-Known Member
Oct 29, 2014
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Eagle Point, Oregon
I've been designing recipes based on water as % of oil weight in the Soap Calc; but I've been reading here in the forum how many soapers use the lye concentration number instead. So, I'm putting the question out "what lye concentration number do you use".

My first soaps were done with 38 water, then down to 35 or so; but I'd like to try 33 water for these one color and other soaps, and my latest recipe on paper, which I'll try to make tomorrow, with 33% water shows a lye concentration of 29.5 with a 5% Super fat and 48oz hard oils.

What lye concentration do those of you who use lye concentration other than water as % of oil, use? And do us use the same lye concentration for simple, one color soaps as you would for more intricate swirls?
I use a 33% lye concentration almost always, unless I am doing a technique/design which needs a lot of time, an FO which I know accelerates, or trying something new (FO or additive) that I think might trace fast. I do use a slow tracing mix, though.
I used 30% water as % of oils for my initial batches, now a days I'm using 40% lye concentration for my solid( single) color soaps and 33% if I want to do any simple swirls. I might go lower concentrations if I ever want to do a fancy swirl.
I think 33% lye concentration works very well for simple soaps. 30% to 31% slows trace a lot for the high lard recipes I use, so I have time to (try to) do swirls, yet the soap is not overly soft after saponification is over. I do see more tendency for mottling and streaking to occur at 30-31% compared to 33%. I would use 40% for a high olive or castile, if I were to make one.

I have never used "full water" and I never use the setting "water as % of oils".
I've been using 30% lye concentration, but I'm considering going a little higher. I do use a slow tracing recipe though.
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I use 33% lye concentration for almost all my soaps, except 100% olive where I go with 40% concentration. I do have a couple of fo's that I know are extremely mean so I lower my concentration to 31%
33% lye concentration (I now completely ignore "water as % of oils", they are two very different things) for well-behaved FOs and simple patterns, 30% lye concentration for new/misbehaving FOs or for swirling attempts.
Like many here, I use a 33% concentration for the majority of my batches, 40% for 100% Castiles, and about 30% to 31% for when I'm working with ornery FO's. I only ever use 'full water' (28%) on those rare occasions that I HP or when I'm working with an extra ornery FO.

I never use the 'Water as % of Oils" box/setting.

IrishLass :)
33% Lye Concentration most of the times for me too. And 30% only when I need to slow down the trace time and mostly for FO's behavior.

40% will only use when and if I ever make Castile again...
I've been very seriously considering going with the 33% concentration for two reasons... 1) it would give me a smidge of playing room if I wanted to mix colors in water or add a smidge to loosen up a batchlet that is thickening up too quick to work with, and 2) because it's just so much easier to do if I decide to master batch. I have yet to brave the master batch beast (for some reason it scares me, why, I dunno). But it would be nice to have already mixed lye that I can just do a quick calculation pour and use.
Thanks everyone for all your input on this. Now I have to get back to Soap Calc and re-do my new recipe for 33 Lye Concentration. I'll save the 30 Lye Concentration for swirls.

I'm tired of waiting too long for these soaps to be ready for un-molding and curing.

Yesterday I made a batch with my new recipe, using 33 lye and I was able to un-mold my little test guest molds this morning; and they un-molded just fine. I'll let the soaps in the wave mold sit till later.

My soap did trace quicker and the addition of sodium lactate probably helped it along. So next time, I'll pour at saponification for sure!
I'm old school - and like to make extra work for myself because I obviously don't have enough sh** to do in the day (it's a gift).

I calculate by hand, and also use a Lye Calc to double check my recipes....
All of ya'll use the SoapCalc one - and I actually don't... I use BB's though I don't use any of their stuff... I've tried SoapCalc and I don't know it just isn't for me. I'll have to give it another go though.. because it does have additional features which have piqued my interest.

And I'm not sure the concentration, but I soap with a water discount, at around 2:1 (water to lye) ratio...
I'm not sure the concentration, but I soap with a water discount, at around 2:1 (water to lye) ratio...

A 2:1 water to lye ratio is a 33% lye concentration. :)

IrishLass :)

Edited to add my list of lye concentration percentages from my notes:

Solution Strength chart
Lye x 1.0 = 50% (the extreme physical limit)
lye x 1.0408= 49%
Lye x 1.083 = 48%
lye x 1.1276= 47%
Lye x 1.15 = 46.5%
lye x 1.173 = 46%
Lye x 1.2 = 45.45%
lye x 1.222 = 45%
Lye x 1.25 = 44.44%
Lye x 1.272 = 44%
Lye x 1.3 = 43%
Lye x 1.38 = 42%
Lye x 1.4 = 41.66%
lye x 1.439 = 41%
Lye x 1.5 = 40%
Lye x 1.564 = 39%
Lye x 1.6 = 38%
Lye x 1.7 = 37%
Lye x 1.75 = 36%
Lye x 1.8 = 35.7%
lye x 1.857 = 35%
Lye x 1.9 = 34.5%
lye x 1.94 = 34%
Lye x 2 = 33%
Lye x 2.1 = 32%
Lye x 2.225 = 31%
Lye x 2.3 = 30%
Lye x 2.448 = 29%
Lye x 2.57 = 28%
Lye x 2.7 = 27%
Lye x 2.84 = 26%
Lye x 3.1 = 25%
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33% Lye and 67% water

How many ounces or cups are in 33% lye?

How many ounces or cups are in 67% distilled water?

How do you measure it on scales (like the KD 8000) until it's the right ounce?