Using carb tabs rules out a problem with the amount of priming sugar or with the priming solution not being properly mixed. If the bottles have spent 3+ weeks at room temp and aren't carbed, then maybe our bottle caps are the issue.
I had two batches of uncarbed beer. Couldn't figure out what the issue was. Bought a new bag of bottle caps and bam, problem solved. Not sure what the problem was but the caps just werent sealing properly...
Drinking:Smoked Dunkelweizen; Imperial Nelson Sauvin Pilsner; American Brown
On Deck: ??