How to prevent water from evaporating during emulsification?

Adi

Hello,

My name is Adi and I'm making a water based hair product which requires emulsifying both heated water and oil phase. I mix them inside a double boiler with a hand blender.

However I noticed from the finished product's weight that water is evaporating. This way I don't know how much water is actually used in my product. Any advice on how to prevent water from evaporating?

Thank you!
Adi

ashish

For making an emulsion, one should use enclosed system which would prevent evaporation of water to a certain extent or on basis of experience of preparation of 1 or 2 batches, chemist should take extra water to make up losses.

luiscuevasii

You could add propylene glycol or glycerine to the water phase to increase the boilling point, or as @ashish said you could simply add more water.

Microformulation

Honestly in Commercial Manufacturing, in many cases the evaporative water loss is considered minimal and not compensated for.

Some Formulations (Saponified Shave Creams come to mind) the water loss is crucial. In that case the evaporative water loss is calculated in the lab and a "guesstimate" of the amount of water needed to be replaced is made. This is done in scale-up usually.

David

luiscuevasii - adding pg or glycerine  won't really work unless you add a lot - see table below

http://www.dow.com/optim/optim-advantage/physical-properties/vapor.htm

luiscuevasii

Thanks @david for the material, i was confused , glycols are used to prevent crystalization and avoid freezing in water solutions.

MakingSkincare

As you are making this at home you could use cling film/plastic wrap to cover the water phase container.  You can also weigh the product at the end and make up for any water loss.

Mulayam

To avoid loss of water during emulsification I do the following-
1- note down the weight of the container used for water phase
2- weigh all the ingredients in this container
3- heat the water phase over ten degrees than required temperature for mixing with oil phase
4-add the weight of the container and the ingredients from the water phase in the formula - A
5-tare the balance. Put a folded kitchen towel on the balance ( this is for the hot water phase container), tare the balance to zero, weigh the water phase container with the ingredients.
6- generally the weight is less than the theoretical weight A
7- I add this weight difference + 5% of batch size additional water to make up the water loss during emulsification. It brings down the temperature of the water phase. If it is lower than the required temperature for mixing with oil phase, heat it again. Normally it is not required.
8- also I cover the container by Aluminum foil.

Microformulation

That approach will work for the small crafter but is hardly feasible for professional larger scale manufacturing.

Margaret2

I am a home-based maker & this is what I have been doing for the last 2 months with success:

 I use canning jars for heating my water & oil phases, each in their own jar. I have a small  hole drilled into the center of the snap lid through which  I put my thermometer. Thermometer is held in place  so it does NOT touch the bottom of the jar, with a small clamp. There is negligible loss of water through the hole due to the thermometer being there. 

There is of course condensation on the lid & sides of the jar,  but I doubt I am losing a large amount of water out of the total mass of ingredients. The water loss is the same as what is condensing on the plastic wrap or aluminum foil others have suggested you use to prevent too much water loss, right?

I do not compensate for evaporation while I am mixing, otherwise I would drive myself mad.  WINKY FACE HERE. 

You could have a separate container of water being heated alongside your  water & oil phase containers, to be used just for making up the evaporation loss of your water phase. That way it's also sterile & about the same temp. as your water phase. 

tanelise

I recently made two small batches of lotion (about 400 grams) and each one incurred water loss at about 0.5%. Hardly worth messing with if it's important to you you've got to weigh your batch after mixing to figure out how much you lost and then just make that adjustment on future batches.

I must add however that I only mixed my batch for about 20 minutes with my Silverson and I did not maintain any specific temperature with a hot plate. When my phases reached about 165 degrees I began mixing and batch cooled down by using a small fan. 

The higher your processing temperature plus longer mixing times will result in more water loss.

tanelise

I also meant to add that I heat more than enough water for my batch. When it reaches my desired temperature, I then weigh out the amount required for the formula in a separate vessel. That way, when I begin mixing  I'm starting out with the correct amount of water.

In other words, I don't weigh the exact amount of water and THEN begin heating because that's when you first start to lose your water through evaporation. 

Hope that makes sense.