Lye - Weigh Up or Down?

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diynewbie

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Hey guys! I'm fairly new to soapmaking but I've gotten a lot better at it than I was before. YAY ME! However, I recently changed up my recipe using Soap Calc and I've got a question about my lye measurements. My scale (I actually have three different scales) only weighs in .05 increments in ounces and only weighs in whole numbers for grams. My new recipe calls for 7.92 oz of lye. Now I've read how measurements/weights have to be "spot on" but I'm a little unsure about that as I know you will always have some ingredient residue left over in containers when you start combining everything and mixing. But that's a discussion for another day. My question is, being that my scale only weighs in .05 increments, what would be the appropriate way to weigh out my lye? Would I weigh down and do 7.90 oz or would I weigh up and do 7.95 oz? I don't want to run the risk of not having enough lye for the soap to go thru saponification, but I also don't want the soap to be lye heavy. But would it really matter?

Please weigh in guys (pun intended lol) as I tend to spend my entire Saturday making soap and I want to get started ASAP. Thanks in advance!
 

dibbles

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My scale works the same way. I weigh all ingredients in grams and have never found the miniscule amount of rounding up or down to the nearest gram to make a difference. If you want to weigh in ounces, assuming you have some amount of superfat, the difference between .92 oz and either .90 oz or .95 oz is less than a gram and shouldn't cause a problem either way.
 

DeeAnna

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The old rule of thumb was to round down for lye and round up for fats. I'm quite certain that was a useful rule when my grandmother made soap with her kitchen scale which was accurate to plus or minus a whole ounce.

Nowadays with our more accurate scales ... not so much. I agree with Dibbles -- it doesn't really matter.
 

diynewbie

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Hey Dibbles! I am superfating at 5% so I guess it wouldn’t matter huh? Thanks for responding!

The rule of thumb is to round down for lye and round up for fats. I'm quite certain that was a useful rule when using my grandmother's kitchen scale which was accurate to plus or minus a whole ounce.

Nowadays with our more accurate scales ... not so much. I agree with Dibbles -- it doesn't really matter.
Thanks DeeAnna! Greatly appreciate the response.
 

Zany_in_CO

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The old rule of thumb was to round down for lye and round up for fats.
Good to know! Thank you.

I always round up or down, depending on whether the amount is over or under 0.5 grams. It's just easier to weigh and doesn't make a whole lotta difference.

I do use 0% SF some times -- especially when using high % olive oil or similar. Olive oil contains unsaponifiables and I want to saponify as much of the oil as possible to prevent the "slime" that is characteristic of bars containing 70% or higher olive oil. ;) :thumbs:
 

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