If your asking if the birch can have a good yield and what are the percentages? yes it does have a great yield if you do it properly. close to 100%. but you have to take into acount that youll lose the hydroxl from the efed or suda... and i think since the russians have a site here maybe they should start translating into other languages "español" for one. seems alot of people here have problems expressing themselves.. not trying to be a dick. just think it would save a lot of time.