Accurate measures

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sperry

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I've heard weight, not volume for measuring FO's. True? I'm doing small quantities, and am nervous about measuring .21 ounces. Is there a good way to do that small of a weight? I was thinking of weighing the right amount, then marking that on a pipette, and then going by volume? Anyone using a pipette pump?
 
Yes, you should weigh your fragrances - but that's really a tiny amount! :) Does your scale let you weigh in grams? That might be a little easier, but not much cause .21 oz is right at 6 grams I think - still small. I would probably set an empty cup on the scale, set it to grams, tare it, then use a pipette to drop the FO into the cup until you get 6 grams.
 
I've heard weight, not volume for measuring FO's. True? I'm doing small quantities, and am nervous about measuring .21 ounces. Is there a good way to do that small of a weight? I was thinking of weighing the right amount, then marking that on a pipette, and then going by volume? Anyone using a pipette pump?

I've run into this issue with small batches as well. I've decided to get a small graduated cylinder and measure the volume in ml, and then convert that to weight by approximating the density as 1g/ml. Worst case, I'm overestimating the weight by a little as I doubt any of these will have a density greater than 1g/ml. Plus, I'm think the error associated with weighing such small amounts is greater than that from any in the density estimation.
 
If you're making such small batches that you only need a quarter ounce of fragrance oil (HP generally uses a half ounce per pound of oils), to help with your accuracy, you should probably be measuring everything in grams, since it is so much more accurate than ounces.

But to answer the question, yes, everything (except stuff like oatmeal, exfoliants, etc) should be weighed for accuracy.
 
Use a wooden coffee stirrer to avoid dribbling down the side of the bottle.
Roy

Pouring Essential oil.jpg
 
The problem about converting a small weight measurement to a volume measurement is the loss of material during the measurement, because there is always a film of liquid left behind when you empty the container. For viscous or oily materials, this residue can be significant. The amount of residue can also vary depending on the temperature of the materials, the cleanliness of the containers, operator error, etc. This can contribute to a lot of error when you're measuring small amounts. If you're serious about measuring accurately, it is better to stick with weighing, use an appropriate scale (one that can weigh 0.1 grams or better) and use procedures that compensate for measuring error -- it's called weighing synthetically and analytically.
 
Thanks. Do you use a pipette pump? They look like they'd be handy, but never seen one.
 
Thanks so much to you all. I have a super accurate gem scale I can use. But I still think I'll at least double the volume. Someone made a great point about FO's sticking to the measuring devise. At the tiny volumes I was contemplating, I think that could screw me up.
 
Weighing Oils

This works well for me. First weigh the empty pot and included equipment. When you have all the oils in the pot you can weigh everything and subtract the empty pot weight to verify your total oil weight.

Put the Brew pot on the scale, I used a SS bowl and plate to rest the Pot on. Whatever it takes to be able to see the scale's screen and make it stable. Be careful not go over your scale's max allowable weight!

The Scale in the picture was mentioned here clink link, thank you! eBay for $21 ppd

Tare the weight to zero, check the accuracy of the scale with a “Calibration Weight” click link

Add the oils to the pot one a time, (don't forget to take out the Calibration weight!) starting with the solid oils, and then tare out scale to zero after each type of oil. Of course it's easy to overshoot and add too much, it's easy to go in after it and take out some. Even with Olive Oil, just use a tablespoon.

There is no advantage to melt the solids first before adding the liquids. It takes about the same amount of heat to melt the solids with or without the Liquids. It would make a difference if you were adding beeswax.

One less bowl to wash and no wasted oils and mis-measuring!
Have fun!
Roy

Weigh soap pot.jpg
 
To answer your question - I use disposable pipettes and a scale that measures to .1 gram. I squeeze out the EO into a scientific beaker tared on my scale.

You can get disposable pipettes very cheaply from a variety of vendors. I got mine from Elements Bath & Body.

I got my scale from TKB trading. It is called the "itty bitty scale" if I remember correctly.

I don't recommend soap batches less than 1 lb (or 500 grams) in size (weight of soaping oils). With smaller batches, small errors in measurement are proportionately larger.

I typically scent at 3% of my soaping oil weight. Less if the EO in question is a known irritant.
 
You can get a scale that measures small amounts for under $20.00. You can get them at hunting supply shops and Lee Valley.
 
Now I dip the coffee stirrer in the Olive Oil. Helps the Essential Oils slide off the stick easier.

Drawed some olive oil into Medicine Dropper before measuring ROE, that stuff is sticky! Also helps to warm the bottle of ROE by putting in a glass of hot water.

Marked the dropper with duct tape, 2 pulls to the tape yielded 1.8 gr. YMMV
Roy



Use a wooden coffee stirrer to avoid dribbling down the side of the bottle.
Roy

Dropper & Olive Oil.jpg
 
Weighing small amounts of EO has always been a challenge. My method is to weigh the bottle and the dropper. Attach a rubber band to the dropper to keep it from falling into the bottle. Subtract the weight of the EO needed. Write these figures down! After removing a dropper full of eo again weigh the bottle and dropper. Continue until the desired weight of the bottle and dropper is reached.
This may seem simplistic and obvious, but not to me until today.
Here 5.6 gr was needed for batch of lotion bars, the eo went into a Pyrex of melted oils, stirred and poured.
Rude

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