Experimental Evidence That Adding Water All at Once or Little by Little Makes Same Lather

[ShavingByTheNumbers]

Summary

• I performed a controlled experiment with one soap (L'Occitane Cade), building one lather with small additions of water and another lather with all of the water at the start until each lather reached equilibrium over a very similar time period
• Both lathers were built with the same initially dry bowl, the same synthetic brush that was almost dry, and the same measured masses of soap (1.0 g) and room-temperature moderately hard (average) water (6.4 g)
• Even though the lathers began very differently, they ended up being indistinguishable, serving as experimental evidence that it doesn't matter whether water is added all at once or little by little

Background

In another thread (B&B URL), the belief was presented that denser, less aerated lather can be built by adding water a little at a time rather than all at once. I was skeptical, but open to the idea, so I wrote that I would investigate the matter:

"I haven't done a controlled study to test the difference between starting with all of the water in the bowl versus adding it slowly, but I hear what you guys are saying. . . . I'll run a little experiment and get back to you guys soon." (B&B URL)​

Experimental Setup

I used L'Occitane Cade with the same synthetic brush, smooth plastic bowl, and room-temperature moderately hard (average) water. The bowl was dry before building each lather, but the brush was wet and then dried as best as I could before each lather. (Before the first of the two official lathers in this experiment, I made a similar lather and dried the brush as best as I could. The first lather was built, the bowl was dried, the brush was dried as best as I could, and then the second lather was built.) So, conditions were virtually identical before each lather. At the start of building each lather, I placed the bowl on my scale, tared the scale, and measured 1.0 g of soap, pressed down on the bottom of the bowl. Then, I added the brush to the bowl and tared the scale. Now came the water and building the lather to equilibrium. When adding water slowly, I placed the bowl with brush on the scale, added a little water, picked up the bowl and built the lather with the extra water, and repeated the process over the course of several minutes until 6.4 g of water in total had been added according to the scale. When adding water instantly, I simply measured out 6.4 g of water into the bowl and built the lather over a similar time period.

Results

In the case of adding water slowly, the lather started extremely thick and low in volume and got thinner with more volume as more water was slowly incorporated. In the case of adding all of the water at the start, the lather was very sudsy near the start, but as the hard soap was incorporated into the mix with agitation, the bubbles became smaller and smaller as the lather was built. In the end, the lathers were indistinguishable in quality and volume. Specifically, the lathers had a matte finish with good thickness and behavior that was in between yogurt and foam. I couldn't tell any difference between the lathers.

Final Thoughts

I realize that my little experiment is only for one soap, and it runs counter to many opinions that building lather slowly with small additions of water can build a denser lather, but my experiment was scientifically done. I didn't measure lather volume with measuring cups—has anyone ever done that?—and more soaps could be tested, but for now, my curiosity is satiated and my concern has subsided.

Feedback is welcome. What do you think?

 

[ShavingByTheNumbers]

Same Principle for Bowl and Face Lathering

I should have mentioned in the OP that the principle of building the same lather regardless of the size of the water additions should apply for bowl and face lathering. Water wouldn't or couldn't be added all at the same time when face lathering, but smaller or larger additions of water should produce the same lather with all other conditions being equal.

 

[patten1969]

I think if you start with the exact same amount of water and soap, in either case it is going to give you the same result no matter what.

 

[matwho]

I always add all of the water from the start and I'm satisfied with the results I get.

 

[slybrewguy]

I'm sure that adding the same amount of water in the beginning vs little by little would produce the same lather. I think the main variable here is by adding all the water ahead of time it can be very easy to under/over do it on the water as well as starting to build with a wet sloppy lather can cause more mess and more loss.

I've always had great success starting with a pretty dry brush and adding water. Same end result hut much less mess and product loss as I build.

 

[Chan Eil Whiskers]

Nice work on this one, brother.

I've not precisely measure or weighed like you did, but I had already drawn the same conclusion, using several soaps. I would say my conclusion was actually more like the basis for an hypothesis, and you've now done the research.

It would be simple enough to replicate the experiment, and simple enough to test with other soaps.

Another hypothesis: There will be people who continue to assert that the water must be gradually added.

These experiments of yours are proving something else as you know.



Your membership to the brotherhood is certified.

Happy shaves,

Jim

 

[major_works]

One anecdotal data point may be derived from my third attempt at lathering Mitchell's Wool Fat on Saturday afternoon. I'd been trying to heed the oft-cited advice to gradually add water to MWF. So I "loaded it like I hate it" with a twice-shaken boar SOC and proceeded to face lather with essentially nothing to show. Scrub, scrub, paint, paint, nothing but thin, dry yucky paste. In frustration, I stuck the brush under the running tap for a second or two and took it back to my face. An instant lather explosion ensued, yielding the best MWF lather I've had. So that, to me, says that the "add water slowly to MWF" trope is just that: a trope.

 

[ShavingByTheNumbers]

I think if you start with the exact same amount of water and soap, in either case it is going to give you the same result no matter what.

I think so, too. As long as you make the lather with similar agitation and time and all things are equal except how the water is added, you should get the same result.

I always add all of the water from the start and I'm satisfied with the results I get.

Me, too, except when the soap bothers me by being too sudsy, but adding the water slowly doesn't solve that problem. The worst offender that I've experienced is MWF.

I'm sure that adding the same amount of water in the beginning vs little by little would produce the same lather. I think the main variable here is by adding all the water ahead of time it can be very easy to under/over do it on the water as well as starting to build with a wet sloppy lather can cause more mess and more loss.

I've always had great success starting with a pretty dry brush and adding water. Same end result hut much less mess and product loss as I build.

I'm only able to start with all of the water in the bowl because I'm measuring mass. Otherwise, I'd build the lather like you said.

Nice work on this one, brother.

I've not precisely measure or weighed like you did, but I had already drawn the same conclusion, using several soaps. I would say my conclusion was actually more like the basis for an hypothesis, and you've now done the research.

It would be simple enough to replicate the experiment, and simple enough to test with other soaps.

Another hypothesis: There will be people who continue to assert that the water must be gradually added.

These experiments of yours are proving something else as you know.

Thanks, Jim! You're right about the ease of replicating the experiment. That's why I wrote the title like I did and started the thread. Doing more experiments is an option. I think it would be great if someone else gave it a go! You don't have to measure mass. Using VOLUME would work GREAT! I would measure the volume of soap using a 1/4 teaspoon by pressing the soap into the 1/4 teaspoon, leveling off the excess, and scooping all of the soap out of the 1/4 teaspoon onto the bottom of the bowl. For a 1/4 teaspoon of soap, a good corresponding volume of water would be 2 teaspoons or 1 tablespoon (3 teaspoons). An important detail is making sure that the brush has the same wetness at the start of both lathers. Preferably, a synthetic brush is better for controlling water, but I guess that a natural-hair brush would do. Experimentation could be done with a cream, in which case 1/2 teaspoon or 1 teaspoon might be best. I don't know. Also, experiments could be done with face lathering rather than bowl lathering. I'd like to see someone do this with face lathering, making sure to start with a similarly dry or wet face for both lathers. That would be cool!

Your membership to the brotherhood is certified.

Since you are a founding member of the BOSC, do you have authority to grant a certification? I'd take it, but I'm afraid that I might start something about being in a brotherhood versus being a certified member of it. I don't want to cause a problem.

One anecdotal data point may be derived from my third attempt at lathering Mitchell's Wool Fat on Saturday afternoon. I'd been trying to heed the oft-cited advice to gradually add water to MWF. So I "loaded it like I hate it" with a twice-shaken boar SOC and proceeded to face lather with essentially nothing to show. Scrub, scrub, paint, paint, nothing but thin, dry yucky paste. In frustration, I stuck the brush under the running tap for a second or two and took it back to my face. An instant lather explosion ensued, yielding the best MWF lather I've had. So that, to me, says that the "add water slowly to MWF" trope is just that: a trope.

MWF is my nemesis. I'm going to TRY optimizing it in the near future. If you or someone else could run an experiment with MWF, that would be awesome! Our anecdotal evidence is similar with how MWF seems to explode no matter the water incorporation rate, but we don't have scientific evidence yet.

 

[Chan Eil Whiskers]

Since you are a founding member of the BOSC, do you have authority to grant a certification? I'd take it, but I'm afraid that I might start something about being in a brotherhood versus being a certified member of it. I don't want to cause a problem.

It seems to me that being certified and being committed are much the same.

Since I am the Logic Professor at

...

You might want to take my opinion with a grain of salt.

MWF would be an excellent project. It is a thirsty soap. I've had much better luck bowl lathering it than face lathering it. Why? Don't know.

Happy shaves,

Jim

 

[kingfisher]

I'm sure that adding the same amount of water in the beginning vs little by little would produce the same lather. I think the main variable here is by adding all the water ahead of time it can be very easy to under/over do it on the water as well as starting to build with a wet sloppy lather can cause more mess and more loss.

I've always had great success starting with a pretty dry brush and adding water. Same end result hut much less mess and product loss as I build.

+1. Experimental conditions versus real-world conditions.

 

[santamariasteve]

I believe the result would be the same. Why wouldn't it?

But it's easier and there's less margin for error when carefully adding water a little at a time. Therefore for the average person and for most circumstances it is the more desirable method.

 

[eelhc]

I believe the result would be the same. Why wouldn't it?

But it's easier and there's less margin for error when carefully adding water a little at a time. Therefore for the average person and for most circumstances it is the more desirable method.

This is the way I see it... whether it's making lather, making pie crust or mixing cement.

It's simple physics/chemistry... no? Lather = soap/cream + water + air.

 

[ShavingByTheNumbers]

I believe the result would be the same. Why wouldn't it?

Some guys think that adding water slowly makes a denser, better lather. (I'm sure that this is because they are following a denser-lather path towards the final result, which can visually cloud the apparent reality that the final result is the same as if they had followed an airier-lather path.) That's why I did my little experiment and started this thread. Whatever result I found, I was going to post it. Anyone else who follows suit and runs a similar experiment with measured mass or volume, either bowl or face lathering, should post the results here, no matter the result.

But it's easier and there's less margin for error when carefully adding water a little at a time. Therefore for the average person and for most circumstances it is the more desirable method.

Agreed.

 

[ShavingByTheNumbers]

This is the way I see it... whether it's making lather, making pie crust or mixing cement.

It's simple physics/chemistry... no? Lather = soap/cream + water + air.

We have to be careful with analogies. Method matters with baking. (I've experienced that myself with identical mass measurements having different results because of a change in technique.) It could matter here, too, but the physics/chemistry does seem simpler here and the experimental evidence indicates that the method of water incorporation does not matter.

 

[ShavingByTheNumbers]

It seems to me that being certified and being committed are much the same.

Yes, but "certifiable" sound crazier.

MWF would be an excellent project. It is a thirsty soap. I've had much better luck bowl lathering it than face lathering it. Why? Don't know.

I agree. Is anyone willing to give MWF a try? A different soap would be good, too. I recommend a 1/4 teaspoon of soap with 2 teaspoons or 1 tablespoon of water. Face or bowl lathering is fine.

 

[eelhc]

We have to be careful with analogies. Method matters with baking. (I've experienced that myself with identical mass measurements having different results because of a change in technique.) It could matter here, too, but the physics/chemistry does seem simpler here and the experimental evidence indicates that the method of water incorporation does not matter.

That's why I said pie crust... IMO the only recipe for pie crust is Flour + Suet + Salt + Pepper... Just add water bits at a time until it's the consistency I need.

 

[ShavingByTheNumbers]

That's why I said pie crust... IMO the only recipe for pie crust is Flour + Suet + Salt + Pepper... Just add water bits at a time until it's the consistency I need.

Ah, but what if you put that mass of dough in the food processor and pulsed it until the dough was really uniform? It would bake differently, right?

 

[eelhc]

Ah, but what if you put that mass of dough in the food processor and pulsed it until the dough was really uniform? It would bake differently, right?

only those who shave with a $20 electric would put pie crust I a food processor.

seriously... there is just no other way to make proper traditional pie crust.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[qVAMPIREp]

This is the way I see it... whether it's making lather, making pie crust or mixing cement.

It's simple physics/chemistry... no? Lather = soap/cream + water + air.

Consider the way chocolate is folded into whipped cream to make a chocolate mousse. Much different that throwing it all into a blender at one time. There is more art here than just masses of X & Y = Z.

 

[ShavingByTheNumbers]

Consider the way chocolate is folded into whipped cream to make a chocolate mousse. Much different that throwing it all into a blender at one time. There is more art here than just masses of X & Y = Z.

You fold water into lather and it doesn't mix together? Doesn't it really get mixed in with very little agitation? That's my experience anyway.