I have a Belgian triple and an old ale that have been aging for about a year now. We are planning on kegging the triple and bottling the old ale. What is the best way to bottle and keg so that both carbonate assuming after that amount of time the yeast will have all settled out.
If you are going to bottle without first kegging the beer then I’d add fresh yeast and prime with sugar using a calculation that sets the temperature at the warmest temperature the beer ever reached and then add 10-15% priming sugar. This accounts for the loss of dissolved CO2 due to temperature and the length of time the beer sat in a unpressurized vessel. There is undoubtedly a better formula to determine CO2 loss due to time but this is what works for me.
Force carbing and bottling off the keg would be easier.
If you are going to the trouble of adding yeast and sugar why not kreusen? It will have a better chance of success than just adding yeast and sugar to already conditioned beer.
FYI, Kreusening or krausening is adding actively fermenting wort to already finished beer for carbonation purposes.