Okay, I think I may be ready to try masterbatching, so I'm reaching out to the all knowing ones on the forum! When I masterbatch, so I just add enough of my lye water (I'm thinking of just doing it at my regular 2:1 mixture to store) as the amount of water in the recipe, correct? Sorry I'm so stupid at math! Thanks in advance...
Whatever concentration of masterbatch you use (I think most people have 50% instead of your 33%), you must make sure you use enough to
get the correct lye amount that your recipe requires. So first you focus on the amount of lye, not the amount of water.
If your recipe requires 5.3g lye, then you add as much lye solution as you need to take care of that 5.3 g lye. If your masterbatch is 50%, then you will have 5.3 g lye + 5.3 g water in it (so 10.6 g masterbatch total).
Next, you have to make sure that your water/liquid amount is good. So, if you need, e.g., 12 g water in your recipe, then --- since you have already added 5.3 g with your masterbatch lye solution --- you will need to add 6.7 g extra.
If your masterbatch solution is 33%, the numbers will be different; but you still need 5.3 g lye in your recipe, and that's what you have to focus on. You have to add 5.3 g lye, so your masterbatch in your case will contain 10.6 g water (since it is 1:2 ratio). Again, if your recipe needs 12g water total, you'll need to add 1.4g water extra.
I think the easiest way to think about this is as if the lye and water were just sitting next to each other in your masterbatch. (Which is not the case since it is a solution, but for math purposes it is easier.) You treat the lye part as lye, and treat the water part as water. You just have to make sure you know how much lye and how much water "is sitting" next to each other in your masterbatch. If your solution is 50%, then they are matched up -- equal lye, equal water. So whatever masterbatch amount you have, half of it is lye, half of it is water, and you want to count them as such in your recipe. If your solution is 33%, then you get twice as much water as lye. So whatever masterbatch amount you have, 1 third of it is lye, 2 thirds of it is water. You still count the lye as lye, the water as water.
Okay I think I tend to overexplain everything.... sorry.