Originally Posted by dougjones31
If your sample came from a 4.5 gallon batch then the gravity reading would be expected to be a little higher than the Target specific gravity, because you have the same amount of the thicker unfermentables but they are floating in less water therefore the gravity is higher and never will reach the target gravity.
If you add .5 gallon of water then the gravity would be less. You are increasing the volume by 1/9th so your gravity would drop 1/9th of the difference between your gravity reading and 1.000.
(1/9 * .026) = .0028
if you add .5 gallons of water to your 4.5 gallon batch the gravity would drop to @ 1.0232. You would still be 5 points off. SO let it sit a while longer to finish up.
Ok, I'm gonna be stupid now
Adding water would actually "change" the composition of the brew.
Taking some brew out
of the carboy shouldn't, in my view.
If that were the case then how about when you take a sample for a reading. Your hydrometer is not floating in 5 gals or even 4.5, it's floating in just a few ounces or brew. By what you have explained above, why wouldn't that reading be different than if you floated the hydrometer in a 5 gal bucket?
So by what you are saying above it would seem that a 5 gal batch of brew being racked into a bottling bucket from a carboy, would have a hydrometer reading get higher
as the carboy emptied into the bottling bucket?
My batch was 5 gals. My OG reading was from 5 gals. I would say that my FG reading was from 5 gals also, just with .5 gal removed...not evaporated, just left behind. I think it's density would remain the same.