Testing Lactose Amounts Before Brewing

[theheadonthedoor]

Is there a way to test amounts of lactose before brewing? I know that lactose doesn't ferment out so can I just add some to a single beer to get an idea and go from there?

I got some crazy stuff planned but I'd rather not ruin batches if I have the chance to play it safe.

Also, has anyone tried to add lactose to other types of beers other than stout? I see a couple threads on lactose ipas, but what about saisons, lagers, barleywines, blondes, etc?

Thanks, friends