Back to before the beans, My Caffeine Farm I am new when it comes to designer coffee, but I am very good with plants and can grow almost anything. 

I would like to know if there is something I can do to the soil or plant to boost the caffeine value of my beans?

Thanks
The caffeine content of your coffee will depend on the variety, the method of extraction and the roast of your beans. 

You can see on this paper about caffeine contents of turkish coffee on table 7, that unroasted coffee releases almost no caffeine, while dark roast gives the best release. 

This article also has an interesting comparison on the caffeine content of different varieties.

I've talked to coffee producers who've told me that Geisha has 35% less caffeine than tipica, and there is a variety of Laurina that has only 25% of the caffeine found in tipica. 
I haven't been able to find data on this, but I did find a little data that points to it being in the right neigboardhood.