Saturday, January 9, 2016

Weekend Wonderings: Thickening a shampoo of castille soap and soap nuts with Crothix?

In this post on Crothix, Hemperical Herbs asks: Using Crothix for the first time and I'm having no luck. My shampoo is still thin as water with a foam that sits on top. I have 2 cups of shampoo and used 5 ml of Crothix so far. The base contains a water decoction of amla, shikakai and soap nuts with 1 tbsp liquid castille and 1/2 cup of coconut milk. The pH is on the low end between 5.5 and 6. Any ideas? 

This comment brings up a lot of issues, so let's take a moment to go through them one by one...

The first is the use of volume measurements to make a product. Best practice is to weigh all our ingredients because it's far more accurate than using cups and teaspoons.

You'll notice the recipes on this blog are done by percentage to ensure we get all the ratios right. I like to use 0.5% liquid Germall Plus in my products as the preservative. So in 100 grams of product, I would use 0.5 grams liquid Germall Plus. How much do I use in 100 ml? Not 0.5 ml because 0.5 ml of liquid Germall Plus may not weigh 0.5 grams.

One millilitre of water weighs one gram, but 1 ml of oil won't necessarily weigh 1 gram. 1 gram of glycerin definitely doesn't measure 1 ml. So when you're converting those lovely percentages into ml or teaspoons, you're not actually getting the amount you want. For instance, 1 ml of oil weighs 0.9 grams and 1 ml of glycerin weighs about 1.26 grams. If you use volume for these measurements, you'll have a recipe that may not work because the ratios are out of whack.

Related post: Figuring out the volume of a recipe

Volume measurements can be quite inaccurate, especially when it comes to ingredients that come in pellet form. Is that 1/4 cup shea butter measured before or after it's melted? Is that a heaping teaspoon or a flat one?

If you still aren't convinced about using weight instead of volume, consider this...I have an ingredient called Natrasorb Bath that is incredibly fluffy. 75 ml (almost 1/4 cup) weighs 8 grams or a little more than 1/4 ounce by weight. So if I told you to use 1/4 cup Natrasorb bath to 1/4 cup Epsom salts, it would appear you have a 50-50 mix. By weight, this would be about 8 grams to 100 grams or 7.4-92.6. That's a huge difference!

Finally, if you use a scale, you don't have all those little spoons and cups to wash up when you're done!

Related post: Why we use weighted measurements when we make products

As a result, it's really hard to figure out how much of each ingredient you're using in this product. If you have two cups of shampoo, you have about 500 ml of product. To this you have added 5 ml of Crothix. Does this work out to 1%? Probably not because 1 gram of Crothix doesn't weigh 1 gram.

But for the purposes of this post, let's pretend that 1 ml = 1 gram, so we can figure out that you have added 1% Crothix to this product. You can go much higher than this if you want, and generally I keep adding it until I get the result I want.

There are a few different ways to thicken a product. One is to increase the concentration of the surfactant, which you could do by adding more to the product. You mention you have 15 ml castille soap in 500 ml of product, which works out to 3% soap. (I would generally put up to 40% surfactant in my products.) You mention you have soap nuts in there, too, but I don't know how much is in there, so I can't comment on that.

The second way to thicken a product is to increase the micelle size, which will also reduce the irritation of the surfactants. We can use salt or an ester like Crothix to thicken it. Will your product thicken with salt or does it need Crothix? I have no idea and don't know where to find that information. (I did a search, but couldn't find anything with good, evidence backed information. If anyone has anything like this, please send it to me!)

I have no idea what your product will be like, but I feel I should note that soap is generally not a good shampoo for many different reasons, the main one being the pH. You mention your pH is 5.5 to 6. How did you measure that? I ask because those strips aren't really all that accurate. The best way is to get a pH meter. If you're planning on formulating with alkaline ingredients or making really low pH products with AHAs, a good meter is your friend.

If your pH is 5.5 to 6, you don't have castille soap in the mix any more. Castille soap cannot exist in a pH below 7, so you don't have soap any more, hence the not lathering. The only foaminess you're getting in this product is from the soap nuts, and I'm not sure how they will interact with your hair. (As an aside, I think the coconut milk will repress the sudsing action because of the fat content. Oils tend to reduce foaming and lathering.)

As a final comment - this product needs a preservative. If we use water, we must use a preservative.  As I mentioned recently, there are no exceptions to this rule. Check out the preservatives section of the blog to find one that you like.

To summarize:

1. Please measure by weight and not volume. When you measure by volume, you can't be accurate and it will throw your recipes out of whack. Plus, you don't have to clean up loads of spoons and measuring cups after a day of creating lovely things.

2. You really don't have any castille soap left in this product because the pH is too low. The soap nuts are the only ingredient offering bubbles or foam.

3. I have no idea if soap nuts can be thickened by salt or Crothix because there's no good, evidence backed information out there that I could find. Can it be thickened by gums? Maybe. I honestly don't know.

4. Soap is generally not a good shampoo for hair because of the pH.

My final answer? I'm afraid I have no idea if Crothix will thicken soap nuts. Sorry.


Kim Vermeiren said...

Do you have any tips on cleaning a ph meter?
I like to add stearamidopropyl Dimethylamine to my conditioner but it needs a ph of 4.5-5.5. My conditioner is the only reason for using my ph meter, I'm no fan of using it. According to instructions I read, you're not allowed to touch the little thing that measures the ph (on my meter it looks like a little glass light bulb without the wire). But if you can't touch it, how do you clean it? At the start of measuring my conditioner is pretty thick so it clings to the meter with a vengeance. I would like to be able to desinfect everything and end up with a useable ph meter.

On a second note, I use lactic acid to lower my ph. Before adding this to my conditioner, my conditioner is very thick (like, stick a spoon in and it will stand straight for hours, thick). By the time I brought my ph to 5 or close it becomes pretty liquid. I can easily pass it through a pump and it doesn't leave any airpockets in my bottle (don't you just hate it when that happens?). It's not like a large amount of liquid was added that can account for this change in consistency so I assume it's lowering the ph that causes this. Why does this happen and is there a way to prevent it? I like the consistency like this but when I label it with something like "butter" or "cream", this is not exactly the consistency that goes with it...

B from Brussels, Belgium said...

I read somewhere that you cannot use an electronic pH meter to measure the pH of emulsions. Any truth in that?

Elisabeth said...

I have (experimentally) used a soapnut infusion as a shampoo, though I wasn't going to waste thickeners on it. Turned out I've had better results with any cold-processed soap I've made (CP soap at least contains emollients and humectants in the form of superfatting oils and glycerin, even if the pH is admittedly on the high side.) I might use soapnuts to wash my hair again if I get stranded on a desert island, but only as a last resort.
(Though I have to say, remembering that misadventure has me rearing to make "proper shampoo and conditioner" again. Waiting for an order of honeyquat, panthenol and BTMS-50 to arrive..)

Bunny said...

Kim, I work in a chemistry lab where we use pH meter just like you described... We use q-tips and water to gently scrub off the glass bulbs!

B, a pH meter works because the glass creates a thin membrane between the solution inside the meter and the product you're trying to measure... so hydrogen ions travel to or from the meter (depending on acidity) which it uses to calculate pH. In a liquid the ions can travel really easily, but if you're trying to measure something really thick... like a cream or heavy emulsion... it won't work well because nothing can flow between that membrane.

Hope this helps!