Gushed like coke

[imabeerpig]

Hi everyone,
I get around 4 bottles from each brew and keg the rest.
Never had this problem before. When I added some sugar to the 4 bottles they instantly gushed up like shaken coke ??
Brew was 23 days old and was a pretty straight Morgan's Australian Bitter.
Can of Morgan's,
500gm Light malt extract,
500gm Dextrose,
200gm Corn Syrup extract.
US-05 Yeast.
23 days in fridge at around 18deg.
What could cause this.
I have let the bottles settle and then capped them.
Wondering if they will explode ??.
Has anyone got any clues on this issue.
I am wondering if for some reason it was still fermenting but it should not have been after so long.

 

[barls]

its just co2 coming out of solution left over from fermenting. add your sugar first.

 

[yankinoz]

Did the beer warm as you were bottling or just before?

 

[imabeerpig]

Thanks for the reply, this was my 25th brew using kits and some extras and have never had this happen before. Caught me by surprise. Like the idea of adding the sugar first.
Now a day later and the bottles look ok. The beer when kegged, had no signs of any foaming and went in like any other, it was just the few bottles that foamed up.
There was no change to the temp during kegging. I usually cold crash for a week or so but had no room this time as both my temp controlled fridges were in use with other brews.

 

[NewtownClown]

the sugar formed nucleation points which released co2 that was in solution. no sugar in the keg so no foaming. you didn't cold crash this brew, so the beer was warmer than normal when you bottled causing the co2 to come out of solution easier.