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If your beer is at final gravity, you can prime it as you would any normal beer based on the amount carbonation you want. In order to properly prime your beer, you will need to know your residual CO2 in solution. This can be determined from temperature and good priming sugar calculators take this into account. For aged beers, especially beers which have been aged in barrels or a similar porous vessel, the starting CO2 may be lower than the numbers produced from these calculators due to off gassing while the beer is aging. We recommend using [http://jeffreycrane.blogspot.com/2015/06/blending-calculator-ph-abv-and.html Jeff Crane's "Blending Calculator" (in progressextension of Michael Tonsmeire's "Blending Calculator")] for priming calculations with aged beer.

If your beer is at final gravity, you can prime it as you would any normal beer based on the amount carbonation you want. In order to properly prime your beer you will need to know your residual CO2 in solution. This can be determined from temperature and good priming sugar calculators take this into account. For aged beers, especially beers which have been aged in barrels or a similar porous vessel, the starting CO2 may be lower than the numbers produced from these calculators due to off gassing while the beer is aging. Tomme Arthur from The Lost Abbey reports that the starting values he sees in barrel aged beers range from 0.2-0.6 volumes of CO2<ref name='Tomme on the Sour Hour'>[http://www.thebrewingnetwork.com/the-sour-hour-the-lost-abbey/ Tomme Arthur from the Lost Abbey on the Sour Hour]</ref> (~51 minutes in). Brewers may choose to partially force carbonate their beers to know the starting CO2 exactly as well as limit the CO2 required from bottle conditioning. The Lost Abbey carbonates to 1.5 volumes of CO2 before priming and bottle conditioning for the remaining carbonation<ref name='Tomme on the Sour Hour'/> (~52 minutes in). Alternatively, a product used in measuring residual CO2 for champagne called a [https://www.reddit.com/r/TheBrewery/comments/6ba8i8/using_a_carbodoseur_to_figure_out_co2_in_solution/ Carbodoseur] can be used to estimate residual CO2 after long aging. See [https://www.facebook.com/groups/MilkTheFunk/search/?query=carbodoseur these MTF threads] on experiences using the Carbodoseur and the [http://www.allafrance.com/notices_pdf/99200-va_FR.pdf Carbodoseur calibration table]. If no effort is made to determine residual CO2, 0.4 has been quoted as a good estimation for aged beer <ref>[https://books.google.com/books?id=l5UIBAAAQBAJ&pg=PA271&lpg=PA271&dq=michael+tonsmeire+residual+co2&source=bl&ots=IQm2_NOAYC&sig=PuhumzttcB_qQHLmNzzGcnmIzDg&hl=en&sa=X&ved=0ahUKEwi_49e-tKDUAhUH6GMKHVBqDj4Q6AEIPzAE#v=onepage&q=michael%20tonsmeire%20residual%20co2&f=false Tonsmeire, Michael. American Sour Beer: Innovative Techniques for Mixed Fermentations. Brewers Publications. 06/15/2014. ISBN-13:9781938469138. Pg 271.]</ref>.

If your beer is not at final gravity, but you have a good idea of where it will finish, then you can prime taking into account remaining gravity points----- to do. See [http://jeffreycrane.blogspot.com/2015/06/blending-calculator-ph-abv-and.html Jeff Crane's "Blending Calculator" (extension of Michael Tonsmeire's "Blending Calculator")[Packaging#Final_Gravity|Final Gravity]] for a re-yeasting and priming calculatormore information.