Taste testing is not a very sound method of determining purity. The first thing I would recommend is a freebase test, meaning drop a small sample into a test tube filled with lye/water solution. If there is ephedrine, it will clear the water from a milky white and white/yellow globs should form. Upon sitting, those globs should float to the surface.
If it passes that test, do a melt point test. If you don't know how, type in "melt point test" on google, then go get a thermometer.
Ephedrine melts at 216C-217C. Anything else is bullshit!
By the way, my guess is when you start adding your sample to the lye, it will fume ammonia, as most of the crap out there is just plain old ammonium chloride - which tastes REALLY salty. It also melts ice quite well but will not do much else.
Chinese my ass! Just because it's from China doesn't mean it shouldn't be pure.