-Lactose, maybe 1/3 lb at the last 5 - 15 minutes of boil.
-With the coffee just poor it in when fermentation starts to slow but before it really stops. the remaining convection will mix it thoroughly then just wait as usual for everything to settle and clear up some.
-If you brew the coffee hot then don't worry about pasteurizing it just poor it in hot. If you use a cold brew refrigerator technique, then just before adding, strain and raise the temp of the coffee to 170*F for 5 minutes then add in hot.
-You will only need about a cup of strong strong coffee (maybe 1 cup grounds to 1.75 cups water. I don't really know the absorption rate of coffee).
I don't know if I would pasturize the coffee, that defeats the whole purpose of cold-brewed coffee.
"You don't brew ice coffee by cooling down coffee that has been brewed normally. During the cooling process there would be excessive loss of volatiles during the cooling process, unless you can cool the brewed coffee without exposing it to any air." (
That Perfect Cup)
It seems as though taking cold-brewed coffee, heating it, and then cooling it again, will touch off this process all over again, which defeats one of the primary reasons why cold-brewing is such a good way of putting coffee into beer.
If you've ever made cold coffee with espresso shots, you'll get a pretty acrid flavor, and many people think that comes from the cooling of the coffee. Similarly, reheated coffee is pretty nasty.
I know sanitation is paramount for beer brewing, but I think it can be done safely without pasteurizing. When I cold-brew, I do it in a growler, so I am working with glass. It's easy to sanitize, you could even sanitize with some star-san or something, and it doesn't react with the coffee like plastic sometimes can. I know of course there is a risk of introducing something yucky from the beans themselves, but I think the risk is somewhat negligible.
Competing opinions?