Monday, April 1, 2013
(Long) Weekend Wonderings: How to heat and hold on a stove, substituting surfactants. and where contaminants in our products arise?
In this post, Love writes: I know that heating and holding is very important but how can I control that the heat won't go above 70˚C? On my stove, which is a generic stove, there are 3 different settings (1, 2 and 3). The problem however is that there's no way of knowing how hot each of the settings are.
We don't heat our products directly on the stove top because our ingredients could burn! Instead, create a double boiler (aka bain Marie or water bath) so the water does the heating for us. If you can boil water on your stove top, you have enough heat to heat and hold!
Fill a pot with a reasonable amount of water. Set it to boil. In the meantime, weigh out your ingredients into a heatproof container, like a Pyrex jug. When the water has boiled, turn down the temperature and place the Pyrex jug into it. The ingredients will be heated by the water. Stir regularly. And definitely get yourself a nice thermometer. (I love candy thermometers for this job!) I think you'll be surprised at how hot the ingredients can get. Feel free to increase the heat from time to time if you need it, but make sure your containers aren't bouncing around and the boiling water isn't spitting up into your products or all over the counter tops.
How do we define a double boiler?
Question: What options are there for double boilers?
Creating products: Heating and holding
Questions about heating vessels
In this post on interpreting surfactant names, Simone asks: Just a quick question - do you find a significant difference between ALS and ALeS, enough to warrant resourcing ALeS? I have found a couple of body wash recipes that call for both products. I have substituted SLeS for the ALeS but would like to know what difference the substitution has made. If you believe it enchances the overall product can you tell me who sells it - I have checked out most of the usual suppliers but without success.
ALS - ammonium lauryl sulfate - is not considered to be a mild surfactant, whereas ALeS - ammonium laureth sulfate - is. I don't recommend using SLS or ALS simply because they are not considered mild surfactants. SLeS and ALeS are considered mild.
As for the difference between SLeS and ALeS, I think I can see a difference. I can use higher levels of the ALeS - up to 60% for some mixtures whereas SLeS is around 40% - and it seems to thicken better than SLeS. (Note: This is just my opinion.)
I bought my ALeS from Voyageur Soap & Candle, but I can't seem to find it there or at any of my normal suppliers now. Hmm...Anyone have suggestions?
As for using ALS and ALeS in a body wash, consider substituting just about any other surfactant for the ALS for a milder product. ALS thickens well with salt, so if you want that quality, look for a surfactant like that.
Surfactants - the section
In an e-mail, Debashree asks: I've spent a lot of time this past week trying to decide which preservative(s) I should use for my DIY creations. I am perhaps more confused now than I was at the beginning of the week :-( So I thought I would come to you with a fundamental question. In the ingredients used for making a water based product, distilled water does not have pathogens (I am hoping); nor do the oils. The heat and hold stage ensures that anything nasty in the hydrosols or other ingredients get killed. So how do the pathogens get introduced into the creation? Is it from the air? Does that mean that if I could store a preservative free lotion in vacuum, it would never spoil?
The contamination can come from anywhere when we're making products. From the air, our breath, our hands, a spoon, the heating vessels, the mixer blades, the bottle for the product, and so on. We can clean as much as we want, but there will always be something that manages to hang around for a bit. We do everything we can to follow those good manufacturing practices, but the reality is that no environment can be completely sterile.
As for putting something in a vacuum container, perhaps, but there might be something in the container, in the funnel or pipette as you put it into the container, and the always curious person who has to open the container and look inside!
When looking for a preservative, you want to choose something that is a broad spectrum preservative or a combination of things that will kill yeast, fungi, and bacteria. My preferred preservatives are Liquid Germall Plus for water containing products and Phenonip for anhydrous ones, but you will have to do some experimenting to see which ones you like best.
Preservatives section of the blog
Why use a preservative?
Preservatives: What can get into our creations?
Have a question? Hie thyself to the Weekend Wonderings comment post and ask away! You could see your question here next Saturday or Sunday!