Crack is an impure form of freebase. It's as simple as that. Doesn't matter how this kicked about and questioned: it is what it is.
When using the water/ammonia/ethyl ether method: the freebase precipitates out and leaves ALMOST ALL of the impurities behind.
When using the baking soda method: the above doesn't happen.
While both may result in a rock that contains the same resulting chemical: the one is purer than the other.
1g of freebase does not equal a 1g of Crack in terms of alkaloid (Cocaine) content.
Freebase melts as a clear and colorless liquid on the gauze and there is no snap, crackle, and pop either. The snap, crackle, and pop from Crack comes from the baking soda (that's where Crack got its name from). That's best case scenario i.e. could also come from whatever other cut is present.
Unfortunately: the water/ammonia/ethyl ether method usually results in a big loss (depends on how badly the Cocaine HCL is cut). But that difference is the cut.
Only problem you have nowadays is that Levamisole also precipitates out with the freebase when using the water/ammonia/ethyl ether method. There's a way to get rid of this too but it's not something you're going to do at home in the kitchen I'm afraid. But let me also say: I never had to contend with Levamisole back in the day (it wasn't a thing) and most of the documentation I've seen on this is actually anecdotal. The science has been limited to the analysis and detection of Levamisole in HCL. Not in freebase (nothing that I've found anyway thus far).
The only reason Crack became a thing and freebase died out was because of the inherent danger of the chemicals (ethyl ether being highly flammable) and the time it takes i.e. if freebase is not allowed to dry COMPLETELY it will not vaporize and may even combust. Worst case scenario (Crackheads not known for their patience): fuck all happens and you end up picking up the phone and ordering shit Crack from your dealer! Ask me how I know!
Still don't believe there's a difference? Do the test. Below is a link (but there are many others) to Erowid (good 'ol tried and tested Erowid) that pretty much sums it up and gives you the instructions (same as those I used decades ago). To begin with you'll be shocked, nowadays, as to just how much Cocaine is in that gram you just purchased. And there is no comparison when it comes to the difference between the two when hit. Anecdotally and based on experience: freebase, for some reason, doesn't (didn't) result in fiendish behavior, (as much) paranoia, jitters, and eliminated the necessity to be melting a new rock while still exhaling the previous hit!
Depending on how anal you wish to get with this:
You could go from Cocaine HCL, to freebase using the water/ammonia/ethyl ether method, then from freebase back to Cocaine HCL. Time consuming. And there'll be an inevitable loss (probably huge nowadays). But you'll have pretty pure Cocaine HCL and, if you insist, you could then make Crack from that (using baking soda) as this would bulk it up again, you'd be known for your rocks, and you'd have a bunch of very loyal customers that'd pay a hefty premium to boot. As they say: t-r-u-s-t me!
Any questions?
Yeah I know: I've been called on this a few times. But I question the background or knowledge of those that have indeed called me on this. There's a few, possibly not that many, things in life I'm an expert on and have the experience to back it up. This is one of them.