Scientific Soapmaking

Scientific Soapmaking
Kevin M. Dunn
Summer 2008
$Revision: 1.1 $
1
Acknowledgements
Copyright © 2008 Kevin M. Dunn
Acknowledgements
•
Mike Lawson/Columbus Foods
2
Why Teach Soapmaking?
Why Teach Soapmaking?
•
Thriving cottage industry
Why Teach Soapmaking?
Why Teach Soapmaking?
•
Thriving cottage industry
•
Soapmakers generally come from a cooking/craft background
Why Teach Soapmaking?
Why Teach Soapmaking?
•
Thriving cottage industry
•
Soapmakers generally come from a cooking/craft background
•
Soapmakers are interested in the chemistry of their craft
Why Teach Soapmaking?
Why Teach Soapmaking?
•
Thriving cottage industry
•
Soapmakers generally come from a cooking/craft background
•
Soapmakers are interested in the chemistry of their craft
•
If gen-ed students can imagine themselves as soapmakers, they
will become interested in the chemistry
Why Teach Soapmaking?
Why Teach Soapmaking?
•
Thriving cottage industry
•
Soapmakers generally come from a cooking/craft background
•
Soapmakers are interested in the chemistry of their craft
•
If gen-ed students can imagine themselves as soapmakers, they
will become interested in the chemistry
•
Experiments are designed to solve real-world problems
Let’s Make Soap
Let’s Make Soap
•
100.00 g Delight (an oil blend)
•
28.80 g Lye (500 ppt NaOH)
Let’s Make Soap
Let’s Make Soap
•
100.00 g Delight (an oil blend)
•
28.80 g Lye (500 ppt NaOH)
•
But how are we to weigh?
Weighing Synthetically
Weighing Synthetically
•
Place cup of water on balance
•
Press tare button
•
Use pipet to transfer water to second cup
•
What if we overshoot?
•
What about the water in the pipet?
Let’s Make Soap
Let’s Make Soap
•
100.00 g Delight (already weighed)
•
28.80 g Lye (weigh synthetically into oil)
Let’s Make Soap
Let’s Make Soap
•
100.00 g Delight (already weighed)
•
28.80 g Lye (weigh synthetically into oil)
•
Shake vigorously for 60 seconds
•
Pour into styrofoam cup
•
Measure temperature
Oil and Water
Oil and Water
Glyceryl Trilaurate
Glyceryl Trilaurate
O
O
O
O
O
O
Saponification
Saponification
Saponification
Saponification
O
NaOH
O
O
O
O
O
NaOH
NaOH
↓
O
Na
O
OH
OH
OH
O
Na
O
O
Na
O
Saponification
Saponification
•
Oil + 3 NaOH = Glycerol + 3 Soap
•
Each molecule of oil requires 3 molecules of NaOH
Saponification
Saponification
•
Oil + 3 NaOH = Glycerol + 3 Soap
•
Each molecule of oil requires 3 molecules of NaOH
•
What happens if you provide only 2 molecules of NaOH?
Saponification
Saponification
•
Oil + 3 NaOH = Glycerol + 3 Soap
•
Each molecule of oil requires 3 molecules of NaOH
•
What happens if you provide only 2 molecules of NaOH?
•
What happens if you provide 4 molecules of NaOH?
Saponification
Saponification
•
Oil + 3 NaOH = Glycerol + 3 Soap
•
Each molecule of oil requires 3 molecules of NaOH
•
What happens if you provide only 2 molecules of NaOH?
•
What happens if you provide 4 molecules of NaOH?
•
We measure oil and NaOH by weight, not by molecules
Saponification
Saponification
•
Oil + 3 NaOH = Glycerol + 3 Soap
•
Each molecule of oil requires 3 molecules of NaOH
•
What happens if you provide only 2 molecules of NaOH?
•
What happens if you provide 4 molecules of NaOH?
•
We measure oil and NaOH by weight, not by molecules
•
Each gram of oil should require a specific weight of NaOH for
complete saponification
Saponification Value
Saponification Value
Theoretical saponification value of glyceryl tristearate:
1 mol Oil
? g KOH = 1000 g Oil
890 g Oil
= 189 ppt KOH
µ
¶µ
3 mol KOH
1 mol Oil
¶µ
56 g KOH
1 mol KOH
Experimental saponification value of tallow: 190-200 ppt
¶
Saponification Value
Saponification Value
Theoretical sodium saponification value of glyceryl tristearate:
1 mol Oil
? g NaOH = 1000 g Oil
890 g Oil
= 135 ppt NaOH
µ
¶µ
3 mol NaOH
1 mol Oil
¶µ
40 g NaOH
1 mol NaOH
¶
Experimental sodium saponification value of tallow: 135-143 ppt
Saponification Value
Saponification Value
• SV
= weight (mg) of KOH needed to saponify 1 g of oil
• SSV
• AR
= weight (mg) of NaOH needed to saponify 1 g of oil
= weight (mg) of alkali actually used to saponify 1 g of oil
Saponification Value
Saponification Value
• SV
= weight (mg) of KOH needed to saponify 1 g of oil
• SSV
= weight (mg) of NaOH needed to saponify 1 g of oil
• AR
= weight (mg) of alkali actually used to saponify 1 g of oil
• SV
of Delight is 211.5 ppt KOH
• SSV
of Delight is 150.8 ppt NaOH
Saponification Value
Saponification Value
• SV
= weight (mg) of KOH needed to saponify 1 g of oil
• SSV
= weight (mg) of NaOH needed to saponify 1 g of oil
• AR
= weight (mg) of alkali actually used to saponify 1 g of oil
• SV
of Delight is 211.5 ppt KOH
• SSV
of Delight is 150.8 ppt NaOH
•
Since Lye is 500 ppt NaOH, we have used an AR of 144 ppt
NaOH
•
Why?
Lye Discounting
1 Day Old
6
4
2
0
140 144 148 152 156
Alkali Ratio (ppt NaOH)
Total Alkali (ppt NaOH)
Total Alkali (ppt NaOH)
Lye Discounting
11 Weeks Old
6
4
2
0
140 144 148 152 156
Alkali Ratio (ppt NaOH)
Checking In
Checking In
What are the temperature and consistency of your soap?
Measurable quantities
Measurable Quantities
•
Finished soap
• Total alkali
• Moisture content
• Hardness
Measurable quantities
Measurable Quantities
•
Finished soap
• Total alkali
• Moisture content
• Hardness
•
Raw materials
• Saponification value
• Lye concentration
• Free fatty acid
Free Fatty Acid
Free Fatty Acid
•
Real-world oils may contain “free” fatty acid
•
How can we measure it?
Titration
Titration
Titration
Titration
•
Add 50 mL ethanol to Erlenmeyer flask
•
Add 4-5 drops 1% phenolphthalein
•
Add 4.18 ppt KOH until solution is faintly pink
•
Solution is now “neutral”
Weighing Analytically
Weighing Analytically
•
Place coconut oil bottle on balance
•
Press tare button
•
Transfer 30-40 drops of oil to Erlenmeyer flask
•
Replace oil bottle on balance and read weight
Gravimetric Titration
Gravimetric Titration
•
Place 4.18 ppt KOH bottle on balance
•
Press tare button
•
Add KOH to Erlenmeyer flask until faintly pink
•
Replace KOH bottle on balance and read weight
Acid Value
Acid Value
YY.YY g Std 4.ZZ g KOH
? g KOH = 1000 g Oil
1.XX g Oil
1000 g Std
µ
¶
YY.YY
=
4.ZZ ppt KOH
1.XX
µ
•
What is the Acid Value of your oil?
¶µ
¶
Acid Value
Acid Value
YY.YY g Std 4.ZZ g KOH
? g KOH = 1000 g Oil
1.XX g Oil
1000 g Std
µ
¶
YY.YY
=
4.ZZ ppt KOH
1.XX
µ
•
What is the Acid Value of your oil?
•
Why did we get different values?
¶µ
¶
Free Fatty Acid
Free Fatty Acid
•
Free Lauric Acid = 3.570 AV
•
What is the Free Lauric Acid content of your oil?
Free Fatty Acid
Free Fatty Acid
•
Free Lauric Acid = 3.570 AV
•
What is the Free Lauric Acid content of your oil?
•
Which oil would saponify quicker?
Extended Investigations
Extended Investigations
•
Dreaded Orange Spots
Extended Investigations
Extended Investigations
•
Dreaded Orange Spots
•
Seizing
Extended Investigations
Extended Investigations
•
Dreaded Orange Spots
•
Seizing
•
Superfatting vs Discounting
Extended Investigations
Extended Investigations
•
Dreaded Orange Spots
•
Seizing
•
Superfatting vs Discounting
•
The Water “Discount”
Lye Concentration
Lye Concentration
•
What is the normal, correct, or standard lye concentration?
Lye Concentration
Lye Concentration
•
What is the normal, correct, or standard lye concentration?
•
Ann Bramson, Soap: Making it, Enjoying it (1972)
25-27%, 26% average
Lye Concentration
Lye Concentration
•
What is the normal, correct, or standard lye concentration?
•
Ann Bramson, Soap: Making it, Enjoying it (1972)
25-27%, 26% average
•
Susan Cavitch, The Soapmaker’s Companion (1997)
26-29%, 27% average
Lye Concentration
Lye Concentration
•
What is the normal, correct, or standard lye concentration?
•
Ann Bramson, Soap: Making it, Enjoying it (1972)
25-27%, 26% average
•
Susan Cavitch, The Soapmaker’s Companion (1997)
26-29%, 27% average
•
Robert McDaniel, Essentially Soap (2000)
33-38%, 34% average
Lye Concentration
Lye Concentration
•
What is the normal, correct, or standard lye concentration?
•
Ann Bramson, Soap: Making it, Enjoying it (1972)
25-27%, 26% average
•
Susan Cavitch, The Soapmaker’s Companion (1997)
26-29%, 27% average
•
Robert McDaniel, Essentially Soap (2000)
33-38%, 34% average
•
Anne Watson, Smart Soapmaking (2007)
30-37%, 33% average
The Soap Formula
The Soap Formula
•
Lye = 50.00% NaOH, 50.00% distilled water
•
Coconut1000Lye348
Coconut1000Lye348Aq174
Coconut1000Lye348Aq348
The Soap Formula
The Soap Formula
•
Lye = 50.00% NaOH, 50.00% distilled water
•
Coconut1000Lye348 (50.00% NaOH “Low-Water”)
Coconut1000Lye348Aq174 (33.33% NaOH “Medium-Water”)
Coconut1000Lye348Aq348 (25.00% NaOH “High-Water”)
Processing Soap
Processing Soap
•
100 g oil + water + lye into 500 mL plastic bottle
•
Shaken 15 sec on a paint shaker
•
Gently swirled until trace
•
Poured into an Upland experimental mold
•
Incubated at 140◦F for 4 hours
Questions
Questions
•
What do we want to know?
Questions
Questions
•
What do we want to know?
•
Does the initial water portion affect the final moisture content?
•
Does it affect the curing time?
•
Does it effect the hardness of the soap?
•
Is there a danger of separation?
What Can We Measure?
What Can We Measure?
•
Moisture content of soap over time
•
Hardness of soap over time
•
Alkalinity of soap over time
•
Separation of soap
What Can We Measure?
What Can We Measure?
•
Moisture content of soap over time
Initially from formula, follow weight loss over time
•
Hardness of soap over time
•
Alkalinity of soap over time
•
Separation of soap
What Can We Measure?
What Can We Measure?
•
Moisture content of soap over time
Initially from formula, follow weight loss over time
•
Hardness of soap over time
Soil penetrometer
•
Alkalinity of soap over time
•
Separation of soap
What Can We Measure?
What Can We Measure?
•
Moisture content of soap over time
Initially from formula, follow weight loss over time
•
Hardness of soap over time
Soil penetrometer
•
Alkalinity of soap over time
Titration with 5 ppt citric acid
•
Separation of soap
What Can We Measure?
What Can We Measure?
•
Moisture content of soap over time
Initially from formula, follow weight loss over time
•
Hardness of soap over time
Soil penetrometer
•
Alkalinity of soap over time
Titration with 5 ppt citric acid
•
Separation of soap
Hardness of top and bottom of bar
Alkalinity of top and bottom of bar
Moisture
Moisture
•
Coconut1000Lye348Aq348
•
Total weight 1696 g
•
Water weight (174 + 348) = 522 g
•
Initial moisture = (522/1696) = 0.308 = 30.8% = 308 ppt
Moisture
Moisture
•
Coconut1000Lye348Aq348
•
Total weight 1696 g
•
Water weight (174 + 348) = 522 g
•
Initial moisture = (522/1696) = 0.308 = 30.8% = 308 ppt
•
Initial bar weight 141.32 g; Final weight 113.17 g
•
Weight loss (28.15/141.32) = 0.199 = 19.9% = 199 ppt
•
Final moisture = 308 - 199 = 109 ppt
Penetrometer
Penetrometer
Smaller foot used for hard soaps.
Titration
Titration
How many grams of acid required to titrate a given weight of
soap?
Total Alkali
Total Alkali
Y.YY g Acid
5 g H3Cit
? g NaOH = 1000 g Soap
1.XX
µ
¶ µ g Soap 1000
¶ µ g Acid
¶
1 mol H3Cit
3 mol NaOH 40.00 g NaOH
192.12
1 mol NaOH
µ g H3¶Cit 1 mol H3Cit
Y.YY
= 3.123
ppt NaOH
1.XX
µ
¶µ
¶
Palm Oil
Palm Oil
•
Low, Medium, and High Water soaps
•
Identical in other respects
•
Moisture and hardness measured weekly for 60 days
•
Alkalinity measured at beginning and end
Palm Oil
Palm Oil
Batch Code
KMD2007.12.27
A Palm1000 Lye286
B Palm1000 Lye286Aq143
C Palm1000 Lye286Aq286
111
200
273
Moisture
A
B
C
200
54
60
74
Alkali/ppt NaOH
Initial
Final
Top Bottom Top Bottom
1.8
4.9 0.3
0.9
1.8
1.4 -1.7
-0.2
0.5
0.3 -1.7
-0.1
Hardness
10
kg/scm
300
ppt
Moisture/ppt
Initial Final
100
0
5
0
0
30
Days
60
0
30
Days
60
Coconut Oil
Coconut Oil
Batch Code
KMD2008.1.8
Moisture/ppt
Initial Final
D Coconut1000Lye348
E Coconut1000Lye348 Aq174
F Coconut1000Lye348 Aq348
Moisture
D
E
F
200
41
88
109
Hardness
10
kg/scm
300
ppt
129
229
308
Alkali/ppt NaOH
Initial
Final
Top Bottom Top Bottom
0.4
0.5 -0.6
-0.3
-0.1
-0.2 -1.7
-1.0
0.1
0.2 -1.8
-0.4
100
0
5
0
0
30
Days
60
0
30
Days
60
Olive Oil
Olive Oil
•
Medium and high water soaps separated
•
What can I do to accelerate trace?
Olive Oil
Olive Oil
•
Medium and high water soaps separated.
•
What can I do to accelerate trace? Add clove oil.
Olive Oil
Olive Oil
Batch Code
KMD2008
Olive1000Lye264
Olive990 Clove10 Lye259
Olive990 Clove10 Lye259 Aq130
Olive990 Clove10 Lye260 Aq260
Moisture
1.7A
3.5A
3.5B
3.5C
300
ppt
104
103
187
256
200
36
43
61
67
Alkali/ppt NaOH
Initial
Final
Top Bottom Top Bottom
0.3
0.2 -3.2
-0.4
-0.4
-0.7 -0.7
-0.7
-0.4
-0.4 -0.8
-0.7
-0.7
6.2 -1.1
-0.2
Hardness
10
kg/scm
1.7A
3.5A
3.5B
3.5C
Moisture/ppt
Initial Final
100
0
5
0
0
30
Days
60
0
30
Days
60
Delight
Delight
•
Delight = Olive390Palm280Coconut280Castor50
Delight
Delight
Batch Code
KMD2008.2.17
A Delight1000Lye288
B Delight1000Lye288 Aq144
C Delight1000Lye288 Aq288
112
201
274
Moisture
A
B
C
200
Alkali/ppt NaOH
Initial
Final
Top Bottom Top Bottom
-0.2
0.2 -1.0
-0.4
-0.4
0.3 -3.1
-0.9
-0.9
0.9 -3.7
-1.3
48
89
104
Hardness
10
kg/scm
300
ppt
Moisture/ppt
Initial Final
100
0
5
0
0
30
Days
60
0
30
Days
60
Delight
Gel Phase
•
Delight1000Lye288Aq50
Tmax 151◦F after 180 minutes
Never reached gel phase
Total alkali: 1.3 ppt (top), -0.2 ppt (bottom)
Delight
Gel Phase
•
Delight1000Lye288Aq50
Tmax 151◦F after 180 minutes
Never reached gel phase
Total alkali: 1.3 ppt (top), -0.2 ppt (bottom)
•
Delight1000Lye288Aq100
Tmax 156◦F after 165 minutes
“Very dry vaseline” at 145◦F after 210 minutes
Total alkali: 0.5 ppt (top), 0.1 ppt (bottom)
Delight
Gel Phase
•
Delight1000Lye288Aq200
“Vaseline” with beads of oil at 151◦F after 195 minutes
Tmax 154◦F after 210 minutes
Total alkali: -0.2 ppt (top), 4.0 ppt (bottom)
Delight
Gel Phase
•
Delight1000Lye288Aq200
“Vaseline” with beads of oil at 151◦F after 195 minutes
Tmax 154◦F after 210 minutes
Total alkali: -0.2 ppt (top), 4.0 ppt (bottom)
•
Delight1000Lye288Aq250
Tmax 156◦F after 165 minutes
“Jello” with layer of oil at 156◦F after 180 minutes
Total alkali: -0.2 ppt (top), 8.7 ppt (bottom)
Conclusions
Conclusions
•
I encountered no problems with lye concentrations up to 50%.
Conclusions
Conclusions
•
I encountered no problems with lye concentrations up to 50%.
•
High-water Olive and Delight soaps separated.
Conclusions
Conclusions
•
I encountered no problems with lye concentrations up to 50%.
•
High-water Olive and Delight soaps separated.
•
More water delays trace.
Conclusions
Conclusions
•
I encountered no problems with lye concentrations up to 50%.
•
High-water Olive and Delight soaps separated.
•
More water delays trace.
•
Low-water soaps start out hard; medium- and high-water soaps
may or may not “catch up.”
Conclusions
Conclusions
•
I encountered no problems with lye concentrations up to 50%.
•
High-water Olive and Delight soaps separated.
•
More water delays trace.
•
Low-water soaps start out hard; medium- and high-water soaps
may or may not “catch up.”
•
“Gel phase” was observed only for medium- and high-water
soaps. Since all soaps were fully saponified, gel phase is not essential. In fact, when separation occurred, it always happened
during gel phase.
Conclusions
Conclusions
•
I encountered no problems with lye concentrations up to 50%.
•
High-water Olive and Delight soaps separated.
•
More water delays trace.
•
Low-water soaps start out hard; medium- and high-water soaps
may or may not “catch up.”
•
“Gel phase” was observed only for medium- and high-water
soaps. Since all soaps were fully saponified, gel phase is not essential. In fact, when separation occurred, it always happened
during gel phase.
•
Saponification and curing are two separate processes.
Recommendations
Recommendations
•
Decide on a standard lye concentration and always use that
when making soap.
Recommendations
Recommendations
•
Decide on a standard lye concentration and always use that
when making soap.
•
You can always add extra (water, milk, etc.) to delay trace or
decrease initial hardness.
Recommendations
Recommendations
•
Decide on a standard lye concentration and always use that
when making soap.
•
You can always add extra (water, milk, etc.) to delay trace or
decrease initial hardness.
•
If oil separates from the soap, try decreasing the amount of (water, milk, etc.).
Recommendations
Recommendations
•
Decide on a standard lye concentration and always use that
when making soap.
•
You can always add extra (water, milk, etc.) to delay trace or
decrease initial hardness.
•
If oil separates from the soap, try decreasing the amount of (water, milk, etc.).
•
Be aware that soaps may continue to lose moisture, even after
60 days.
Recommendations
Recommendations
•
Decide on a standard lye concentration and always use that
when making soap.
•
You can always add extra (water, milk, etc.) to delay trace or
decrease initial hardness.
•
If oil separates from the soap, try decreasing the amount of (water, milk, etc.).
•
Be aware that soaps may continue to lose moisture, even after
60 days.
•
Make lye only from NaOH and water.
Checking In
Checking In
What are the temperature and consistency of your soap?
Summary
Why Am I Teaching You to Teach
Soapmaking?
•
There is a market for soapmaking instruction
Summary
Why Am I Teaching You to Teach
Soapmaking?
•
There is a market for soapmaking instruction
•
Soapmaking can motivate gen-ed students
Summary
Why Am I Teaching You to Teach
Soapmaking?
•
There is a market for soapmaking instruction
•
Soapmaking can motivate gen-ed students
•
Online soapmaking communities are fraught with MSU
Summary
Why Am I Teaching You to Teach
Soapmaking?
•
There is a market for soapmaking instruction
•
Soapmaking can motivate gen-ed students
•
Online soapmaking communities are fraught with MSU
•
I’m lonely
Summary
Organizations
•
The Handcrafted Soap Makers Guild (www.SoapGuiild.org)
•
The Saponifier (www.Saponifier.com)
•
Scientific Soapmaking (www.ScientificSoapmaking.com)