measuring preservative

[corrine025]

Ok so I use germall plus for my lotions. It says to add at .5% so I have a recipe that has 10 oz of other ingredients, my calculations say 1 gram of preservative is what I need. Did I do that right? Seems like such a small amount

 

[DeeAnna]

Actually you need 1.4 grams for that recipe to dose at 0.5%. At 1 gram, your preservative dose would only be 0.35%, but that's within the recommended dosage range for Germall Plus.

Yep, that's not much. I use a scale that weighs to 0.1 g to measure stuff like this.

I'll concede that measuring small amounts of Germall Plus is a big pain -- it is thick and syrupy so it is really easy to pour out waay too much. When pouring, I just try to get it close then gradually remove the excess from my measuring container and reweigh until I get the correct amount. To get that tiny bit of preservative into my lotion, I pour a little bit of my cooled lotion into the Germall Plus container and mix thoroughly, then pour the mixture into the main batch of lotion and mix again.

 

[itunu]

You might find it easier to use this recipe converter which will convert % to grams - http://makingskincare.com/recipe-calculator/

 

[corrine025]

awesome thanks guys! I like the idea of mixing with some lotion and adding back in!

 

[TVivian]

I use a children's medicine dropper. They usually will give you a couple for free if you ask at the pharmacy counter. Then I measure the preservative in the dropper I weigh it. Once I know which marking on the dropper is the correct weight, I write it down and only use that dropper for that product. Does that make sense? I only make very small batches so far.

 

[DeeAnna]

Only problem with using a dropper or pipette is there will be a film of preservative left inside the dropper that introduces a lot of measuring error. This is especially true if the product is viscous (like Germall plus). So you can't just fill the dropper up to the weight you want and empty the dropper into your container. If you do that, you will greatly under-measure the amount of preservative that is in your lotion.

The correct way to use a dropper in a situation like this:

First, fill the dropper with more preservative than you know is required for your lotion batch. At first, a scale will be very useful -- weigh the empty dropper, press Tare, fill the dropper with preservative, weigh, repeat if needed until the weight of preservative in the dropper is a generous amount more than the weight you need for your recipe.

Next, put a container on your scale that you want to weigh the preservative into. Tare the scale. Use your dropper to add preservative to the container until the weight equals the amount of preservative required. Then you've measured accurately.

edit: And maybe you're doing this, TVivian. Didn't mean to imply you weren't -- my apologies.

 

[TVivian]

Yup! That's exactly how I do it and you explained it so much better than I did!
I measure in such small amounts that with the thick consistency, I always poured out too much
before

 

[newlife]

Old thread but hopefully someone will see this. Anyone using Leucidel Liquid SF Max? I am reading that it works better when also adding AMTicide however I can find no mention of how much to use for both. Do you use the percentage recommended for both or do you use a smaller amount of each?

 

[cmzaha]

I use full recommended amount with my dual preservative system. The trick is all the ingredients have to be different.

 

[newlife]

Thanks but what do you mean all the ingredients have to be different?

 

[cmzaha]

Preservatives are usually made up of more than one ingredient at least the one's we tend to use. You do not want to duplicate the active ingredients.