Just kegged a brew, been fermenting nicely at 18.4deg took a FG reading got 1016 but temp was 16.1deg.

is there a conversion factor to work out what the reading would be at 20 deg. or could i give my keg a quick squirt of gas(top tap) and take another one when the brew has warmed to20 deg, although iv'e obviously added priming sugar.
