Tuesday, October 18, 2011

Creating products: Questions about mixing

There's been a lot of interest about mixing our products, and a lot of questions have arisen, so let's take a look at a few of the comments from the post on this topic!

Anonymous asked this question: Hi Susan thank you for the wonderful information so generously given here. After reading you post on blending lotions I wonder if I am over stirring my lotions. I have tried manual, stick blending & mixer but always end up with same result: even thought the finished lotion looks smooth when I put in the pots, the next day or so it starts to look like whipped milk cream that has been over whipped, kind of congealing which gets back to smooth texture after a bit of manual stirring but it doesn't stay smooth for long I have to keep on stirring every few days. Hope you can help me solve the mystery, thank you.

This doesn't sound like a mixing issue: It sounds like your lotion has failed. (Click here for the original and entire post.) If you have to keep stirring it to keep it smooth, it means that you don't have an emulsion - you have an oil phase and and a water phase that don't want to stay together.

Remember, we need three things to make an awesome emulsion in our products...
  • chemical emulsification - this is where our emulsifier comes in. Pick a good emulsifier and use it at the right percentage! 
  • heat emulsification - in general, solubility of our ingredients increases when they are heated. Click here for more about the heating and holding phase of our products. 
  • mechanical agitation of some kind - mixing ingredients so they will stay emulsified. 
If you have a great emulsifier but aren't using it at the right amount, you'll get a fail. I don't think the issue is overmixing...I think the issue is a failed emulsion that has been temporarily held together by a lot of mechanical agitation! Take a look at your recipe and make sure you have the right kind of emulsifier and enough emulsifier for your oil phase, and ensure you are heating and holding for 20 minutes. If you're doing all of these things and you're still experiencing lotion fail, write to me with all the information (recipe, procedure, and so on) and I'll see if I can help further!

Vanillagirl writes: My emulsions are wonderfully stable (thanks to your info) but I find they end up with quite a lot of bubbles. I have been doing 500gm batches as I am new to this and am wondering if stickblending for 20 minutes to emulsify is too long. I subsequently add cooldown phase and sb a further 10 mins to ensure the ingredients are well mixed in. Am I blending too much? Thanks. 

I think you are. Twenty minutes is a long time and although it doesn't seem like you're ruining your emulsions, you're getting bubbles in them and you're taking a total of 30 minutes to mix a lotion. I'm all for mixing, but 30 minutes - that's time in which I could make something else!!! If your lotions are working well, then try mixing for a shorter period of time - say 5 minutes for the combining phase, 5 minutes for the cool down phase - and see if you have fewer bubbles. If your lotions are staying together through sheer will and mechanical emulsification, you might see some problems. But if you're using a well thought out recipe, you'll be just fine!

Leman writes: Also, my creams froth a lot when I use a milk frother. I mean I can hardly fill 50ml into a 100ml jar and I am thinking I must be doing something wrong or frothing too much or the fact that it is a milk frother!. Any ideas anyone? 

I wouldn't use a milk frother to mix your products...it's intended to froth milk, so it's going to mix a ton of air into the product. If you want to mix small batches, consider using a hand mixer with only one beater (I find this works great for my 100 gram batches!) or even mixing by hand (see below)

What's the best way to mix your products? 
Lise comments: I feel incredibly old fashioned-- I mix pretty much everything by hand unless I am doing a whipped butter or whipped cream (I have a whipped cream cleanser that I've done for years). Even then I only use a stick blender. I feel I have much better control this way. I also do whipping cream (the kind you eat) by hand too. :)

I love the fact that we have to clarify what whipping cream is to a group of bath & body crafters! Did I tell you about the time I smeared cake icing all over my hand to test if it was done? Yep, I make more products than I do food...but I digress...

melian writes: i use a stick blender, in fact until this blog i didn't realize you could make a successful (long term stable) emulsion without high-shear blending! i also don't spend 10 minutes (or more) with the sb, either. i think that if i continued with the sb until it cools, i'd have whipped cream rather than a nice lotion. i create the emulsion, then let it sit and stir it with a spoon now and then until it is at the temperature i want for whatever i'm doing next. i have discovered that adding eo or fo when it is cooled down is not the best idea, as unless i hit it with the sb again for a couple of minutes, it will sometimes seep out and gather at the top of my tube of lotion (in other words it wasn't emulsified into the lotion). using the sb at cool-down causes all sorts of whipped cream effect and foam and stuff.

And I like to use a mixer - it can get a bit foamy on top if I go a little crazy, so I do it on a slow speed with the beaters, not the whisk attachments. I also like to use a Kitchenaid if I need to do a large batch, but again I do it on a slow speed with the paddle attachment. If I'm making a body mousse or sugar scrub, I'll do it on about level 4 with the whisk attachment and I'll let it go for a while. Some people love the stick or immersion blender - I find it spatters for me, and my husband likes to reserve it for food.

The key to all of this stuff is to read what you can, then get into your workshop and try out what you've learned. It might work, it might not, but you'll learn something in the process! Then come back here and tell us your experiences so we can learn more!

If you're making little batches, I have a few suggestions for mixing...
  • It sounds like a milk frother might be small enough, but it adds extra air, which isn't necessarily a good thing. 
  • When making small batches, find something that works for you, like a hand mixer, stick blender, or mixing by hand (Click here for my post on the topic of small batch production). I can't imagine making something smaller than 100 grams - so much fiddly work and so many places to make mistakes thanks to 0.1 grams more than you intended. 
  • A tall container - like a beaker - is a better choice than a wide container. I like to use the taller Mason type jars - 250 ml, not wide mouth - to make smaller batches. A shallow container makes it harder to mix. 
Well, that's it from me today. Share more of your experiences and thoughts in this post or in the original post - it's great we can learn from each other!

12 comments:

Tara said...

I use a stick blender until the emulsion turns thick. After that it doesn't seem like it does much mixing, so I turn to the cake mixer, which is much better at scraping the sides of the container. If I start out using the cake mixer, that's when it seems to incorporate too much air.

Lise M Andersen said...

Great postng! It's true, the amount you are making will have a huge impact on what kind of blending method is best. I wrote that I do almost everything by hand. I also typically do small portions at a time- often just 100ml. :)

Always.Looking.4.1.More said...

Susan, thanks for the response you gave about this topic.

Lise, I appreciate your confirmation of what I thought was happening. You seem to have been at this for quite some time so if I may ask a little further or you, will you please go more in-depth about your method of mixing? It sounds like you've had a consistent amount of success at doing this.

1. Was I correct (in my response to your comment - blog 10/13/11) that your formulas rarely, if ever, are foamy unless you want them to be?
2. How long do you mix your formulas, especially the ones you mix by hand? Please tell me/us your method phase-by-phase.
3. I know this might sound small, but how fast are you mixing while you're mixing by hand? Are you doing an easy stir or are you whipping the formulas?
4. How long do your finished products last before you've used all of it? If they last for weeks or months, is there ever a time when you see a breakdown of the formula after much time has elapsed? If so, what method did you use on that batch, and did you try it again using another method of mixing, or a shorter or longer time of mixing?

I may not like mixing by hand but I'll do it if it will produce success.

Robert said...

I can't comment on particular homecrafter equipment as our equipment is somewhat larger with our batch sizes typically in the 180 kg. to 200 kg. range.

Generally,for lotions and creams, we find a slow, continuous, steady mix until emulsification takes place gives the best (and smoothest) results. Higher speeds introduce excess air into the product which is an undesired result.

Certain situations, though, require higher speed mixing. For example, higher speed mixing is recommended to properly disperse xanthan gum in the water phase.

There are general good mixing principles but there is not necessarily one 'right' way to make a particular product. To use the title of one of Woody Allen's films for mixing (and relationships) 'Whatever Works'!

Mychelle said...

I use a stick blender for a few minutes when combining phases, until I have a smooth mixture. I occasionally hand stir as it cools and stick blend for another minute or two when I add my cool down ingredients. Not a ton of mixing but I get a stable emulsion every time. Everyone has their own technique, I love that.

M Konnerth said...

Thank you Susan for getting back to the basics on these posts! I have had successful lotion emulsions (thank goodness) using your instructions. I use a stick blender on and off as my mixture is cooling. I probably zap it thoroughly for about a minute, leave it to check emails or whatever and go back again as it cools down.
I use a hand mixer with one whisk and one mix attachment for my emulsified sugar scrubs. I have noticed that over the course of a week - I will get a film of separated oil on the top of these scrubs. Quite truthfully - I'm not sure if it's the hot weather, or an issue with my technique.
I would love to find a used kitchenaid and am on the hunt!
I can't wait for the next step in this series, hoping that you will address, how the devil we get these lotions into their jars! : )

Anonymous said...

Hi Susan, thank you for your reply. After following your instructions carefully I attempted once more to get a stable emulsion, however the result is pretty much the same, the lotion looks beautifully smooth on the first day, the second day it starts to look like a chocolate mouse in texture which smooths out as I stir it.
My recipe is as follows:

Water phase
52% H20
5% Aloa vera
3% Glycerine
2% H. oats
2% O. esters

OIL PHASE
5% jojoba oil
15% shea butter
2.5% EPO
2.5 avocado oil
6% E-wax
2% cetyl stearyl alcohol
.5% preservative
.5% fragrance

h20& oil phases warmed 70oC held for 20min
poured oils to water
mixed with fork for 1 minute
used mixer on low speed for 3 min
when cooled added preservative & FO
mixed for further 1 minute or so

Sorry for the long post. Hope you can work out what is wrong with my formula or procedure

Thank you again for your help

Elly

Susan Barclay-Nichols said...

Thanks to everyone for your great comments! It just shows that there isn't a right way to do it, as long as we're mixing the product enough to help with emulsification. We do have to watch for foam and bubbles, though!

Hi Elly. I have two questions - one, could you be you're mixing too much air into it?, and two, which e-wax are you using? If you're using something like Polawax, you'll need to up it to 6.75%. To clarify, it's more a like a mousse with whippy air pockets in it rather than a pudding? Like I said, the only answer I know to that problem is to use mixers on low speed rather than whisks on high...but you have described your mixing process, so I'm really stumped!

Anonymous said...

Susan thanks for responding so promptly. Yes the texture of the cream looks like there is some air in it, I'll have to watch it more carefully when I mix. I will increase the % of emulsifier (polarax)and see if that makes a difference. Thanks a million for your help.
Elly

Always.Looking.4.1.More said...

To Robert:

Robert,thanks for your response about equipment, mixing, and emulsification. I asked to hear from a chemist and you spoke up. There's so much to get into and I dropped the ball on thanking you earlier. So thanks! :-)

Now that comment about xanthan gum has me thinking because I don't remember having any problems with it dispersing, and I've used both the hand mixer and manual mixing methods since this post.

Vanillagirl said...

Hi Susan. Thanks for your your reply (Oct 2011) I just wanted to detail my formula for you, as I am wondering if I am using too much emulsifier as my lotions get quite thick.
73.5% water
2.5% glycerin
1.3% Neo Defend Plus (preservative)
.7% Sodium Citrate
14% oils (1% of which is Shea Butter)
4% Olivem 1000
2% Cetyl Alcohol
1% Fragrance
.5% Vitamin E T50
1% Rosemary Oleoresin Extract
What do you think of this formula?
Thanks for your reply

Susan Barclay-Nichols said...

Hi Vanillagirl. To make a lotion thinner, you could remove the cetyl alcohol or reduce the oils and add more water. I wouldn't go less than 4% Olivem 1000 as you might not get the emulsifying you want!