Get a lot of questions about cooking up ketamine so figured would write this thread for the people.
Firstly the point I will go over is the benefits of cooking, of which are few in the grand scheme of things (fairly minimal). Many people cook because in their opinion it produces a "softer", finer ketamine for insufflation. Physically it may be more fine, yes, but technically crushing it to a fine powder will achieve nearly identical results. It's up to preference. You may be loosing some K while cooking though if you are not very precise or careful.
Cooking, in the true sense of the word, applies only to vials of K. This is when a vial is made from liquid to crystal. But the term has leaked into the recook niche.
FAQ: Q: "Why people who have crystal ketamine cook it?" A: They want it to be a fine powder for snorting and do not realize that simply crushing it up gives the same result. Some claim that it makes the K physically softer or more fine. Of course they have a lot of superstition attached to it as well (similar to different 'types' of LSD molecules when this is simply not true either).
Q: "Does it make it more powerful?" A: Absolutely not. If anything you lose some on the cook if not skilled.
Q: "What is the effect of cooking it?" A: Generally, a waste of time.
Some say when you dissolve the crystals and cook rather then just crushing you get a much lighter density powder (higher volume) that goes a lot further its also less hassle then crushing the crystals which can often be very hard. To each his own.
Techniques: Double Boiler Microwave
Double Boiler - take your K, mix with some water in a sauce pan or pot. Once you have another pot boiling underneath of it, put the second pot on top (or use a real double boiler). Mix infrequently, and as the water evaporates the K will precipitate and collect. Be careful not to burn it.
Microwave - Mix K with water, put into a porcelain tray / bowl. The time it takes for the microwave to evaporate the water will depend on your microwave, so just keep an eye on it. I think this method is sketchy personally. You don't need much water either, a few ML's should suffice for a gram. One dry scrape with a razor and snort.
Edit: One more tech: Open air bazar. Take the K, add about 1-2mL per gram, (crush be fore adding) and mix with water. Put on a windowsill or in the sunlight and let nature run it's course. Scrape and collect with a razor.
MulanKetma
Oh man, I miss the vials I used to get. I always evaporated them in a shallow Pyrex pan with a hairdryer on low. Only took about 10min a vial, and didn't heat it up to much. The low heat and the airflow was all that was needed. Then I'd bust out the razor, scrape the dish, and pass the "party platter". Those were good times indeed.