In a recent thread I saw a few members discussing whether to use hot or cold water when cleaning the lather off your face.
They didn't have any definite reasons on why they felt that way but knew what worked best for each of them.
I wanted to make a reply without sidetracking the OP's thread so I thought I would get the basics of the science out here.
Now it's been years since I've been in a science class but I had a good grasp at it. I had to look up some spellings but I had the basics of it still stuck in my head. I may not be 100% on everything but I'm pretty sure I'm close. Like I said it's been a while.
Washing With Cold vs Hot Water.
Water is good at cleaning because it's highly attracted to hydrophilic molecules and will push away other water molecules to instead bond with the hydrophilic molecules which causes the hydrophilic substance to blend with the water. Hydrophilic substances are anything that easily becomes soluble in water like sugar & salt.
Cold water will pretty much clean in the same way as hot water it just takes longer to do it. The kinetic energy of hot water causes the water molecules to spread out and move faster which makes them bond with the hydrophilic molecules easier and faster. More space in between water molecules means there are more water molecules able to reach the hydrophilic molecules to bond and since they are moving at a faster rate they find and bond to them faster.
Ok but how does this help any grease or oil on your face since everyone knows oil doesn't bond with water right?
Well oil and grease are hydrophobic which means water has a stronger bond to other water molecules than it does the hydrophobic molecules and won't bond with them. It just kind of goes around them. That's where soap comes in!
To make it simple soap has two ends one that is hydrophobic and the other is hydrophilic. The hydrophobic end breaks up the oil by bonding with tiny drops of the hydrophobic oil while the hydrophilic end bonds with the water molecules. In turn the oil is pulled off your face and suspended in the water.
Shaving With Cold vs Hot Water.
So it is basically true that hot water is better to use for cleaning off your face and equipment while shaving but since you are shaving your face you do have to take your skins reaction to hot and cold water into effect.
Cold water will contract your skin causing your hair to stick out straighter and stiffer which will make shaving them easier.
Hot water will make cleaning your skin easier but it's said that it can also dry out your skin by removing natural oils.
I know heat also brings fresh oxygenated blood to the surface and sweat causes salt to cool and dry the skin.
The question is does the soap strip these oils from you face anyway and the water washes away the salt?
With helpful info from SRNewb, hot and cold water doesn't actually "open" or "close" your pores. I do wonder does the contraction and swelling of the skin effects pore opening size at the surface?
I'll update this section if any new info is added.
http://badgerandblade.com/vb/member.php/83554-SRNewb
Conclusion?
What I'd advice is going back and forth between warm and cold water which I believe a lot of member here do.
I use warm water while making my lather, then I switch to colder but not freezing water to shave. I use warm water to wash the soap off my face the rinse with cold water before I put on my aftershave.
Use the correct temperature of water to get the required reaction at the necessary time.
Everyone has their own method but I thought I'd give some helpful info if anyone was interested on why those methods work they way they do.
If you know for a fact that I was off on anything I said please feel free to mention it. Like I said it's been a while.
They didn't have any definite reasons on why they felt that way but knew what worked best for each of them.
I wanted to make a reply without sidetracking the OP's thread so I thought I would get the basics of the science out here.
Now it's been years since I've been in a science class but I had a good grasp at it. I had to look up some spellings but I had the basics of it still stuck in my head. I may not be 100% on everything but I'm pretty sure I'm close. Like I said it's been a while.
Washing With Cold vs Hot Water.
Water is good at cleaning because it's highly attracted to hydrophilic molecules and will push away other water molecules to instead bond with the hydrophilic molecules which causes the hydrophilic substance to blend with the water. Hydrophilic substances are anything that easily becomes soluble in water like sugar & salt.
Cold water will pretty much clean in the same way as hot water it just takes longer to do it. The kinetic energy of hot water causes the water molecules to spread out and move faster which makes them bond with the hydrophilic molecules easier and faster. More space in between water molecules means there are more water molecules able to reach the hydrophilic molecules to bond and since they are moving at a faster rate they find and bond to them faster.
Ok but how does this help any grease or oil on your face since everyone knows oil doesn't bond with water right?
Well oil and grease are hydrophobic which means water has a stronger bond to other water molecules than it does the hydrophobic molecules and won't bond with them. It just kind of goes around them. That's where soap comes in!
To make it simple soap has two ends one that is hydrophobic and the other is hydrophilic. The hydrophobic end breaks up the oil by bonding with tiny drops of the hydrophobic oil while the hydrophilic end bonds with the water molecules. In turn the oil is pulled off your face and suspended in the water.
Shaving With Cold vs Hot Water.
So it is basically true that hot water is better to use for cleaning off your face and equipment while shaving but since you are shaving your face you do have to take your skins reaction to hot and cold water into effect.
Cold water will contract your skin causing your hair to stick out straighter and stiffer which will make shaving them easier.
Hot water will make cleaning your skin easier but it's said that it can also dry out your skin by removing natural oils.
I know heat also brings fresh oxygenated blood to the surface and sweat causes salt to cool and dry the skin.
The question is does the soap strip these oils from you face anyway and the water washes away the salt?
With helpful info from SRNewb, hot and cold water doesn't actually "open" or "close" your pores. I do wonder does the contraction and swelling of the skin effects pore opening size at the surface?
I'll update this section if any new info is added.
http://badgerandblade.com/vb/member.php/83554-SRNewb
Conclusion?
What I'd advice is going back and forth between warm and cold water which I believe a lot of member here do.
I use warm water while making my lather, then I switch to colder but not freezing water to shave. I use warm water to wash the soap off my face the rinse with cold water before I put on my aftershave.
Use the correct temperature of water to get the required reaction at the necessary time.
Everyone has their own method but I thought I'd give some helpful info if anyone was interested on why those methods work they way they do.
If you know for a fact that I was off on anything I said please feel free to mention it. Like I said it's been a while.
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