[mdsterken]

I recently brewed an IPA (5 gallons--all grain). It fermented for 3 weeks, then I added 2/3 cup of cane sugar to the fermenter and bottled the beer--a technique I have done consistently for the past 2 years with great results.  The bottles have been conditioning at 70-72 degrees for over one month.  When I open the bottles at room temp they are perfectly carbonated (even arguably over-carbonated).  However, when I chill them to 40 degrees they become either completely flat or only effervescent.  What is going on?  How can I serve COLD beer that isn't flat?
--Mike

[majorvices]

When the bottles are warm the co2 is not absorbed into solution as well. When cold, the co2 will absorb into solution and will stay in solution better and longer. So your beer is just as carbbed when it is cold as when it is warm it is just that the co2 wants to escape faster. As far as why your beer is not carbbed properly there could be a number of things. You aren't waiting long enough or the temp is too cold or you aren't mixing the sugar properly so some bottles are carbbed more than other. Regardless I'd recommend stop measuring and start weighing your sugar. It is more accurate.