Scaling up: From drops to liters

Note: This article is a follow-up on a blog post found here — And I've posted a video showing how we set up the electronic balance here.

When creating a fragrance, I work with dropper bottles and small mixing cups which have screw-on caps. My initial sketch for a fragrance may involve from 50 down to 10 or fewer drops total. Dropper bottles are a handy, but not precise, tool for developing a new fragrance.

mixing pots in use ... lots of them!

Mixing pots with screw-on caps, in use ... lots of them!

Here's the formula, in drops, of a fragrance I developed.

spreadsheet showing drops not yet weighed

Pictured above is my formula measured in drops, the way I originally developed it.

And here are some of the dropper bottles I've used to develop this formula.

aroma materials being used

Pictured above are some of the dropper bottles I used to develop my formula.

If I was going to produce several kilos of oil—juice—for this fragrance, I would not do it based on my satisfaction with a very small trial batch of the fragrance measuring only a handful of drops. Nor would I be writing my formula out in drops. At this point I want to convert my formula to weights and percentages. To do this I must weigh out each ingredient and then, after totaling the weights, calculate the percentage, by weight, of each material.

Weighing out the formula requires the use of a good scale (called a balance) and mine (Acculab VIC-123) is reasonably good, showing weights down to 1/1000th of a gram. A professional perfume creation company would, no doubt, have equipment that was considerably more sensitive and accurate.

Before weighing each ingredient in my formula, I'll bump up the number of drops for each ingredient so that small variations in drop size will be canceled out. Rather than mix a formula with just 30 or even 50 drips, I'll bump the drops total up to 100. Even then if there are some materials I have used in small quantities, say 1/2 or 1/4 drop, I'll bump the total quantity up higher so that no ingredient will get less than two drops in the enlarged batch. In the example shown, my new total was 150 drops.

NOTE: Professional perfumers will almost always use some ingredients in amounts so small that my equipment would have no way of dispensing them properly or measuring their weights. For the independent, "part time" perfumer, ultra small touches must generally be ignored, although there are some tricks that can be used to include faint touches of these materials, albeit with imprecise measurement.

Here now is my setup for weighing out my formula. Notice that I have my notebook handy, ready for me to mark down the weight of each material.

overall setup

Here's my setup for weighing out each aroma material I've used in my formula.

NOTE: If you've never used an electronic balance it's a good idea to test with some junk material, to get the hang of it. They can do some tricks on you if you're not alert.

Now let's get down to business.

First we zero out the scale to make sure our weighing will be accurate. Then we place a mixing pot—one large enough to hold all the drops we will be mixing—onto the balance, weigh it, and record this weight. This is known as the tare weight, the weight of the container itself.

balance set to zero

The electronic balance is now set to zero, ready to begin measuring our project.

At this point you can proceed in several ways. The point is, as you add each ingredient to the mix, you must capture the weight of that ingredient. As for me, after weighing the container, I zero out the scale again with the container on the scale. Now I begin adding drops.

As I add, drop by drop, the drops for each material, I record the new weight after I've finished adding each new material. When I'm finished I have the total weight of the full formula plus, after some subtractions, the weight of each individual material in the formula.

finished bottle

Here's the bottle again, on the electronic balance (scale) now holding the 150 drops of my formula.

Now, since I have the total weight and the weight of each material, I can calculate the percentage—by weight—of each material in the formula. This allows me to scale up production for any size batch. Once I determine the batch size I want, I know what weight each ingredient will contribute to that batch.

Before going into production I will repeat the weighting procedure a second time, as a check against my weight calculations. If my weights the second time vary too much from my weights the first time, through human error in adding drops or by the size of the drops themselves, I'll weigh out a third batch.

formula in percentages

The spreadsheet above shows the final results. The first column is the original number of drops. The second column is the cumulative weight of the formula as each material is added, the third column is the actual weight of the material, and the fourth column is the percentage, by weight, that material contributes to the formula. You can do the math by hand but in this case I chose to do it on a spreadsheet.

Also—essential—I'll test each finished batch with a test blotter to make sure that I've really mixed the fragrance I intended to mix. At this point if it doesn't smell right I can go back and make adjustments. After this, my measurements and percentages ARE the formula.


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Philip Goutell
Lightyears, Inc.


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