OK, OK...simmer down! And that's what I hadda tell my beer last night! So I stumbled on the last bottle of one of the batches I did a few months ago to better understand different yeast brand results on the same wort. After popping the crown off the bottle, I went across the kitchen to get a glass and when I came back I noticed that there was a nice foamy head creeping its way up the bottle neck and was within a couple of millimeters of reaching the top and spilling down the side of the bottle. Not wanting to have a mess to clean up, I began to gently pour my brown ale into my glass in the proper manner, tilted glass and all but to my surprise, I was only pouring out foam! I kept it up until I had a full pint glass of brown foam and only about a finger's width of actual beer in the glass and still a half bottle of beer in the bottle. WTF!? What's going on here folks?? Here's some other data points for you while you put on your thinking caps: The earlier consumed bottles of this batch did not do this. This was the last bottle of a batch brewed in early February this year using Windsor that only got down to a SG of 1020 resulting in a low ABV. I used dextrose for my Priming Sugar. The beer was about 55° F , the glass was a little warmer by some 10 degrees. Here's my thought...as this low ABV was most likely due to under pitching but still the yeast did their job but just took a longer time to do it, like 2 months! The additional sugar AND the remaining sugar added in the bottling process went beyond the point of carbonation that I thought I was calculating for a 2 point something volume of CO2 and went over that but not to the point of a gushing potential bottle bomb. Thoughts??