Terribly frustrating trying to make clears. Of course I can make a clear shampoo in minutes that will work fine, but have no fragrance. That's not much use.
The first problem is NOT to use Tween-20. It kills the viscosity curve. However, the Dehyton-G will effectively emulsify the FO. So I have been doing tests on FOs to see which might work for a clear. In each case I added about a 1/2 tsp of FO to a small beaker, added 1tsp of Dehyton G, and mixed. Then added 50mL of water and mixed. Clear or milky? Results:
1. pear: milky
2. apple: milky
3. almond: marginal. slight cloud
4. cherry: clear
5. kiwi: milky
6. orange: very milky, and it thickened the mixture noticeably
good for a cream shampoo
7. melon+kiwi: marginal, a bit too cloudy
8. chocolate: milky
9. mango: milky
all the above are IFF fragrances.
I tested one from Wellington Fragrance: cherry almond. This was good, completely clear.
Also from a local supplier (unknown brand) I tested:
10. vanilla: milky, and turned the surfactant to water.
11. coconut: milky, and, strangely, turned a yellowy-white instead of pure white.
and BrambleBerry:
12. lime: milky. thickened, so good for cream shampoo.
13. blackberry: milky
14. litsea cubeba: milky
It appears to me that it is difficult to find fragrance oils that can be used in clear shampoos.