One aspect that councils will consider for any home business is the amount of deliveries and times. How will you get green beans delivered or roasted beans shipped out? If you have frequent delivery vans or a truck coming then they will probably say no to your business if it is in a zoned residential area.
Also if you do well and build up a customer base delivering roasted beans to cafes or selling roasted beans via the internet what happens when one neighbour complains to council? - cause you didnt give em their free beans :-) If council then says stop trading how long will it take to setup somewhere else and will your previous customers return after that interval?
I think a roasting business run from a residential area could be profitable when you dont have the overheads of a rented site in a more appropriately zoned area but you need to consider if your business would be viable if you have to use a proper site.
PS. Get all decisions & permissions from council in writing.
Best wishes anyhow :-)