Because ammonia is, as far as I'm concerned, far superior, stronger, cleaner. The ammonia you use is only household ammonia, 10%/ammonia 90%/water. You never bring it to a boil, you only warm it, slightly. Fumes are negligible to virtually nonexistent, and ammonia is NOT flammable at 10% solution. The rock that forms is immiscible with ammonia (cannot chemically mix, like oil and water) so the only remaining ammonia is easily rinsed off. Some people do several rinses to be extra cautious. However, because ammonia is a gas, it evaporates completely, and quickly, which is why it's the predominant ingredient in window cleaner. A thoroughly dried rock cannot retain ammonia. People who have used bicarb for years will argue furiously, terrified to be wrong, but there is no doubt to me it is much stronger, hits you harder. Bicarb rock is bulkier, because the cocaine molecule binds to the bicarb molecule (which street dealers love for you to see.) No matter what you do, soda cook WILL contain bicarb, which you WILL smoke. If you use slightly too much soda, which many, many people do, it will be in there. Moreover, especially for newer users, there is 1001 ways to screw up a soda cook. Ammonia takes me (literally) under 3 minutes to complete (though you need to dry it.) There is virtually no way to screw it up. I could do it on a moving bus. It often returns 90%-95% + weight, if you're original product was good. It is, IMHO, simply a finer, easier, more productive end product. I would never use bicarb again, nor, I may point out, will anyone else I know who's tried this method. When I learned the process I was FURIOUS nobody had known/mentioned it to me before.