First of all, remember the immortal words of Ben Franklin when commenting about the first continental congress, "They are not your friends, they're people you work with, they will screw you first chance they get."
Tell the dude this is what you usually charge for an award winning home craft brew. Make it high, then add 10 percent more to the figure. Now tell him that since he is a good friend, you are going to take 10% off. Ask him how much he needs ....get the money up front.
PS, if he goes for it, IM me and I'll tell you how to make an infection in it.