You rang? Propane is a "CFC-free" propellant. Highly flammable. Under pressure, just plain scary. Do not, under any circumstances, try to light it on fire or let it roll behind a radiator. (Just a joke). Mousses, except the ones with the pump-able tops (non-aerosol mousses or foams) need a propellant to get out of the can. It's the propellant that largely determines the texture of the mousse! Some make big bubbles for a thick, wet mousse and some make little bubbles for a dry-feeling mousse. My understanding is the HFC propellants like difluoroethane or Hydrofluorocarbon 152a make the small-bubble (dry feeling) mouses. The propane or isobutane (or some combination of those 2) propelled mousses make stiff-feeling mousses and if you mix some of these propellants, you can develop a wide variety of textures. The Clariol mousse has Hydrofluorocarbon 152a, and Isobutane, for example.
Then there are surfactants in mousses to keep them fluffy long enough to spread around in your hair - things like Laureth-23, PEG-150 distearate, Oleth-20. That has a lot to do with texture because some will have more "body" and flash-foam action and wet feel than others.
And the polymer for hold which is either something like PVA/PVP that requires neutralization (another formulation issue) or the polyquaterniums which have a conditioning feel to them.
Like asthma inhalers switching to hydroflurocarbons (HFCs instead of CFCs), because CFCs were correlated with ozone destruction over Antarctica and Southern Australia, the new formulations are not always as good as the old ones!

I realize that this is no help at all in choosing a good mousse. I feel your frustration in losing a product you liked for years that was so affordable and reliable. I wish there were a thick, wet, gloppy one with no scent and no itch for myself!
Dear Santa...
Originally Posted by IAgirl
I knew you would be able to explain it! Thanks!
2b/3a, normal/high porosity, fine/medium texture, medium density, low elasticity

Low Poo- Tigi Colour Goddess, Giovanni 50:50, Giovanni TTT (clarify 1X/week)
Condish- CJ Curl Rehab, Giovanni 50:50, Giovanni TTT
Leave In- Slip Detangler, KCKT, Redken Curl Refiner
Treatment- CJ Repair Me! and CJ CR

Dislikes: Too much protein, high glycerin content, and heavy oils