Soapmaking Friend - Recipes Based on Mold Size

[KimW]

Have you found that this works? I've found it does not adjust the recipe for different water amounts. For example, if I leave everything at default (2:1 water:lye; 5% Superfat; 3% FO) the calculator consistently provides a recipe that is 12% too high in weight with volume varying, but always considerably too high of volume. Changing all defaults to minimum provides more accurate results, but again this is because it doesn't appear to adjust anything to account for a higher water amount than 1:1 water:lye. Granted, using a weight calculator can be tricky for volume based measurements. Has anyone else noticed this? I've always done hand calculations and was sort of excited to see this feature, but it doesn't appear to work - or, perhaps I'm using it wrong?

FYI - I don't have permissions to post on soapmakingfriend forum, so I posted here.

 

[Dawni]

I'm rereading again n again what you wrote so I can understand the question haha

Buuuut... I've used this calc from its beginning, with different water amounts, different superfats, CP and HP.. And I've had no problems lol

I'll respond better once I understand haha ✌

 

[AliOop]

When I used the fit-recipe-to-mold feature, I ended up with almost double the batter needed to fill the mold. I triple-checked everything to confirm that my mold dimensions were correct as entered. Seemed like maybe it had used the mold dimensions to calculate oil weight instead of batch weight.

 

[Arimara]

It works fine. I tried it for a smaller mold I have for testing purposes. It stopped my overages.

 

[KimW]

It works fine. I tried it for a smaller mold I have for testing purposes. It stopped my overages.

How much water, superfat and FO do you usually use, Arimara?

@Dawni - rereading my post I think it is confusing. LOL Here's an example:
I have a mold measuring 4" X 3.75" X 2.25" which is 18.7oz volume
If I leave the defaults of -- water: lye ratio=2:1, superfat=5%, FO=3%, the soapcalc provides a recipe that weighs 20.95 ounces
If I change the defaults to, for example, what I use to make M&P base -- water:lye= 3:1, superfat=0%, FO=0%, the soapcalc provides a recipe that weighs 23.39 ounces.
Since volume rarely equals weight, it's not surprising that the weight would be different than the volume of my mold, but not by that much.
When I do the calculation by hand for that mold using 3:1 water:lye ratio with no superfat and no FO, I get 19.1 ounces of weight, which is just the right volume of soap batter for that little mold.

See pics - pay no attention to the oil used. Just how the weight of the recipe changes when the defaults are changed, and notice that the weight of the oil does not. I know the calc is off because it's not adjusting the oil weight when the water weight (water:lye ratio), lye weight (superfat %) or FO are changed, but I was just wondering if anyone else had seen this, or if I was using the tool wrong...

 

[Arimara]

It's not a problem with the calculator. One of the recipes has a 0% superfat. That makes the difference for the same amount of oils.

 

[KimW]

It's not a problem with the calculator. One of the recipes has a 0% superfat. That makes the difference for the same amount of oils.

I see - so if I change the default superfat, then it messes up the calculation?

 

[AliOop]

I agree with @KimW - the calculator does not always calculate the right volume of batter to fill the mold size that you enter. I don't know why, but I know this by experience after having it work perfectly for my smaller mold, and being wildly wrong for my larger one.

 

[Arimara]

I see - so if I change the default superfat, then it messes up the calculation?

To be fair and more accurate, you may want to use your measurements for the recipe but compare the water content with the superfat that you plan to use. I wouldn't call it a calculator error unless the superfats from your screenshots matched. YOu could also just make a 300g batch and see where that takes you. That's the absolute lowest I'd personally go with soap making and it's really not a lot of soap to be made either. Do you happen to have a picture of your mold?

 

[KimW]

To be fair and more accurate, you may want to use your measurements for the recipe but compare the water content with the superfat that you plan to use. I wouldn't call it a calculator error unless the superfats from your screenshots matched. YOu could also just make a 300g batch and see where that takes you. That's the absolute lowest I'd personally go with soap making and it's really not a lot of soap to be made either. Do you happen to have a picture of your mold?

Suppose I could take a pic... It's just a little mold made of sign board plastic that I use for testing recipes.
Measures 4" X 3.75" X 2.25"

 

[Dawni]

Hmmm... I was under the impression that using more water will increase total batch weight, and using less will decrease total batch weight. Isn't it supposed to?

At the same time, especially since you don't add superfat after the cook, more superfat will also increase batch size, less will decrease.

Its different amounts after all... No?
Am I the one who is doing things wrong? Lol

 

[KimW]

Hmmm... I was under the impression that using more water will increase total batch weight, and using less will decrease total batch weight. Isn't it supposed to?

At the same time, especially since you don't add superfat after the cook, more superfat will also increase batch size, less will decrease.

Its different amounts after all... No?
Am I the one who is doing things wrong? Lol

This is what I get for trying to find a way out of doing math! LOL

 

[Dawni]

Lol well I hate math so I haven't done much hand calculations...

200g water for 100g oil = 2:1 = 300g
300g water for 100g oil = 3:1 = 400g

This is how my simple brain works it out, without factoring in anything else lol

 

[amd]

I have found there is an issue when calculating cylinder molds. It asks for radius, and the resulting formula is half what it should be. Yesterday I used this to calculate to fill two 6" cylinder molds (so I entered 12" total length), and I only had enough to fill one of the molds. I think the formula should either be corrected to use radius x 2 or the calculator be corrected to ask for diameter instead of radius.

 

[KimW]

I have found there is an issue when calculating cylinder molds. It asks for radius, and the resulting formula is half what it should be. Yesterday I used this to calculate to fill two 6" cylinder molds (so I entered 12" total length), and I only had enough to fill one of the molds. I think the formula should either be corrected to use radius x 2 or the calculator be corrected to ask for diameter instead of radius.

Yes, I noticed this too, but because I knew the volume of my mold I knew the calc was off, so didn't make the recipe.

 

[lshone]

Have you found that this works? I've found it does not adjust the recipe for different water amounts.

Soapmakingfriends approach to volume calculation is somewhat simplistic.

Your mold volume is 4 x 3.75 x 2.25 = 33.75 cubic inches.

Soapmakingfriend simply multiplies 33.75 x .4 = 13.5 oz of oil. This doesn't take into consideration the superfat or lye concentration.

Because the oil volume is static (13.5) the amount of lye is also static, and only the volume of water will change. Therefore the weight and volume of your batter will vary as you change the lye concentration.

 

[KimW]

Soapmakingfriends approach to volume calculation is somewhat simplistic.

Your mold volume is 4 x 3.75 x 2.25 = 33.75 cubic inches.

Soapmakingfriend simply multiplies 33.75 x .4 = 13.5 oz of oil. This doesn't take into consideration the superfat or lye concentration.

Because the oil volume is static (13.5) the amount of lye is also static, and only the volume of water will change. Therefore the weight and volume of your batter will vary as you change the lye concentration.

Agreed - this is exactly what I am seeing.

So, what I'm hearing is the "resize to mold" feature is working as designed in that it will not adjust the oils (and also therefore the lye) in a recipe if any variable - water:lye ratio, superfat, FO - are not at minimum levels. Meaning, it will only give accurate results if all variables are set to minimum/zero levels. Fair enough. I can work with anything if I understand how it's designed to work.

 

[glendam]

It has not worked for me, sometimes it does, though; but when calculating for a round mold, it was way off.

 

[amd]

Soapmakingfriends approach to volume calculation is somewhat simplistic.

Your mold volume is 4 x 3.75 x 2.25 = 33.75 cubic inches.

Soapmakingfriend simply multiplies 33.75 x .4 = 13.5 oz of oil. This doesn't take into consideration the superfat or lye concentration.

Because the oil volume is static (13.5) the amount of lye is also static, and only the volume of water will change. Therefore the weight and volume of your batter will vary as you change the lye concentration.

What about the cylinder mold calculation?

 

[KimW]

For cylinders, I think they have figured the volume of a cylinder based on the formula for finding half the area of a circle. That is, "pi r squared divided by 2 times height", instead of "pi r squared times height". Or...they have the formula correct, but entered the value for 1/2 of π ...which would be even more weird.