an exposé on the [in]famous bf

During my online research on aromatherapy, I came across a term familiar among many but spoken of only by a few – Blending Factor (BF). Here's a summary based on my limited understanding of the topic.

definition
Blending factor (BF) is an arbitrary numerical value assigned to an essential oil based on its aromatic strength. The value ranges between 1 and 7 (some would go as high as 10) with "1" being the strongest-smelling and "7" the mildest.

application
How do you assign BF to essential oils? You can begin by first selecting, from among all the essential oils that you possess, the strongest and the mildest smelling essential oils. Then, base on those two extremes, compare and rate the rest of the essential oils one at a time. For example, if I have a total of 12 essential oils, I would probably want to:

1. use a smaller scale: 1 – 7
2. choose the strongest smelling essential oil: Vetiver
3. assign the BF to it: Vetiver (B1) where B stands for Base note
4. choose the mildest smelling essential oil: Bergamot (top note)
5. assign the BF: Bergamot (T7)
6. choose the next: Birch (top note)
7. compare it to Vetiver, Bergamot and the remaining 9 oils.
8. assign the BF: Birch (T2) repeat
9. Steps 6 through 8 for the remaining oils.
10. adjust where necessary.

As you can see, from the above example of Birch essential oil, Blending Factor doesn't necessarily correspond to Perfume Note. They are not the same simply because they measure different properties of essential oils. That means to say, while Blending Factor rates essential oils in terms of strength, Perfume Note is based on the volatility of the aroma or how long-lasting it is.

In fact, if you've been checking out the essential oil profiles provided in this blog, you'll make the Scent Life–Perfume Note and Scent Impact–Blending Factor connections.

Before you jump on the wagon...

limitations

Blending is not just about finding out proportions and calculation. Life would be so easy if it were so simple and the world would end up smelling more or less the same. Why so? It is limited precisely because:

1. it measures only one property of the essence;
2. the rating itself is subjective and arbitrary;
3. it ignores the complexity of the compounds within each essential oil; and, more importantly,
4. how these compounds interact with one other when combined;
5. it doesn’t take into account safe dosages when applied on humans;
6. comparison works well when there are only 2 variables;
7. nose fatigue when assigning Blending Factors;
8. oxidation or the aging process within a blend.

The way I see it is that Blending Factor is useful only on paper – it helps by giving me a starting point before I actually begin the blend. If you try blending using only BF calculation, you'll soon realise how flat everything seems to end up smelling. Think of it as cooking. I don't know how you feel aboutThousand Island salad dressing but I sure as hell don't want to have it on my salad every day!

So, never use it on its own, especially for therapeutic purposes because there are many other factors involved which are more crucial.

In aromatherapy blending, synergy overrules all else for its ultimate aim is therapeutic not merely aromatic.