[harbicide]

I don't normally bottle except if I am running out of kegs.  For my last two bottled batches (an RIS and a Strong Scotch) each ended up with highly carbonated (with deformed caps) beers.  For each I used table sugar per an online calculator.  For the first I thought that perhaps I hadn't considered the use of the right temperature that the beer was at.  For the second I paid particular attention to the beer's temp but I still got bombs.  All bottles fill glasses completely with foam (even tried wetting the glasses before pouring).  Both were bottled after 4 weeks and the tastes don't indicate any wild yeasts working.  Any ideas?

[tygo]

What was the volume you bottled, how much sugar did you use, and what was the highest temp the beer reached while fermenting?

Are they all like that or did maybe it not get mixed in completely and some are undercarbed?

[redbeerman]

My guess is that they were not finished fermenting or there is some infection that is chewing on leftover dextrins.

[duboman]

Did you weigh the sugar or measure by cup? Did you bulk prime or add sugar to the individual bottles?

[Jimmy K]

My guess is that they were not finished fermenting or there is some infection that is chewing on leftover dextrins.

This is my answer, unless you didn't mix the sugar completely.

[AmandaK]

1) The beers were not finished fermenting.
2) The sugar was not mixed well.
3) You used volume instead of weight to measure your sugar.
4) Random bottle infection - which usually throw phenolics.

Don't feel too bad - I've done each of those at least once. 

[Joe Sr.]

Both beers would have a high OG.  My guess is that they did not finish fermenting.  Of course, we are just guessing.

What was the final gravity?

IME, high gravity beers take longer to reach terminal gravity.  This would be especially true if you've underpitched.

The only bottle bombs I've ever had were from a saison when I grew impatient and bottled too soon.  It's one of the reasons I don't plan on using Belgian Saison yeast again.

Unless you're sanitation is poor I wouldn't expect all the bottles to be infected (unless the beer was infected in the fermenter) and if the sugar was poorly mixed you would have some bottles that are flat or undercarbed.

[morticaixavier]

Did you bottle with any additional yeast?

If so was it the same strain or a different one from the original?

If the original was a lower attenuating yeast and the bottling strain was a higher attenuator you would get fermentation both from the added priming sugar and some of the remaining longer chain sugars that the original strain left behind.

so it was 'done' as far as the original strain was concerned but not the bottling strain.