So why are my FG and OG never like NB’s?
1: hydrometer is not accurate. A few years back the local club did a calibration night. Out of 10 or so hydrometers, only 1 was accurate.
2: Your volumes are off. Even 1quart can make a big difference in the reading.
3: If you are topping off the fermenter with water, the wort isn’t getting mix well enough for an accurate reading.
4: NB’s numbers are not correct.
How far off are you?
If the OG is 1.048 by NB readings I am always around 1.040.
do you add water to reach your desired volume after the boil?
Extract or all-grain?