Any way to save low carbonation? Carb tabs?

[HootHootHoot]

So I have been having problems of over-carbonating my beers with using the same amount of table sugar for all styles. So recently I started using this website:
http://hbd.org/cgi-bin/recipator/recipator/carbonation.html

In the past I used the "temperature at bottling" as my temp, but later I was told that I should have put the highest temp the fermenting beer was subject to.

So, I used that instead (65 deg).

I was bottling beer that was fresh off a cold crash. I used the correct amount of sugar that this site told me to use. Yesterday was three weeks. I opened a beer and it was about 1/2 carbed, if that. I have no idea where I went wrong.

Is it possible to pop a carb tab into each bottle to save it? Do I just wait?? I've never had a problem with carbonation (aside from low carb with my last batch because I estimated the temp too low). I can't imagine it carbing up suddenly after three weeks already in the bottles in my basement...

Thanks for help. I'm supposed to have this pumpkin batch ready for thanksgiving and Christmas this year. Looks like thanksgiving is a wash and I'm targeting Christmas.

Thanks

 

[BlackGoat]

what temperature are you conditioning them at? how high is your alcohol level in your beer? Both of these could really affect how long it takes to carb up properly. Definitely don't open them up and add any more priming sugar at this point.

 

[HootHootHoot]

Basement temp... I'd say about 60 deg with the cold weather we've had (WI).

Alcohol level is only 4.8%... Not high

 

[BigFloyd]

Basement temp... I'd say about 60 deg with the cold weather we've had (WI).

Alcohol level is only 4.8%... Not high

Three weeks is typical for a 70-75*F temp. At 60, it's going to take 5-6 weeks if the yeast haven't gone to sleep.

 

[lohr500]

I am having a similar problem. Coopers Canadian Blonde kit made as per the instructions, bottled after 12 days in the primary fermenter.
I like a well carbed beer, so I used two carb drops per 500ml PET bottle which should have been more than enough. (Previous wheat beer kits were reasonably well carbed using one and a half carb drops per bottle).
I opened a couple of bottles yesterday, two weeks after bottling and they are very poorly carbonated. The bottles felt pressurised but the beer had hardly any head or sparkle. Tastes OK though.
My bottles have been around 65F. If the yeast has gone to sleep, will it wake up if I move the bottles somewhere warmer or once it has stopped, is that it?
Thanks

 

[BlackGoat]

as bigfloyd said it will take longer at those temps. Either just wait it out, or move the beers up to a warmer part of the house, you want them up around 70 degrees for those three weeks of carbing, then you can move them down to basement/celler temps to condition.