Since I know nothing about brewing I looked online and found recipes for grapefruit wines and such... thought if anyone was interested in using grapefruits for brewing this might be a big help:
FREE GRAPEFRUIT - SAN BERNARDINO
http://inlandempire.craigslist.org/zip/1163416708.html

:::The Ad:::
The fact is, this tree always has grapefruit, they are dropping all over the ground and we do not eat them!
There are ants in the tree, but some spray will solve that.
The tree is very large in my backyard, and teenagers love to climb it, so here is the deal.
Email me if interested, I will then contact you back, and we can set up a good time for you to come out with the teens and bring your ant spray,
The grapefruit is FREE to you, all you need to do is get them. if you have picking tools, great!
I am unable to climb and do much bending and all.
You might want to come out every month and this is fine, too!
I would just rather not keep seeing them go bad all over the ground.

I am going to send the guy an email to get his contact info just in case the ad disappears before anyone contacts him (if they want to take advantage).
--Jo