i dd this for the first time two weeks ago (dex in the keg) the brew was fermented at 12 degrees for two weeks then cold chilled for 2 days, transfered to keg and added 100gm dex to the keg, gassed it to 250kpa and ruined it. it tasted like lolly water and and a painfull gassy pour. i had to leave the kegs out of the fridge to get any yeast left to eat out the sugar so it wasnt so sweet, last time i add sugar as i screwed up 40lt, ill stick to the co2 only next time or add 2 tablespoons only, tried that before and worked really well