Carbonation time: explosive bottles?

[dennybc]

Hi everybody!
I have a cold-crashing American IPA (all grain), which has reached a 1015 FG (this value is stable since three days) after a 3-weeks fermentation (1 week primary, 2 week secondary). I added Isinglass before the cold crash.
The actual FG is equal to the expected, considering the OG (which was 1062).
I consulted some priming sugar calculators, and all of them suggest a 5 g/L dose. I'm a bit worried because my usual priming dose is about 1 g/L, but in fact in these years i brewed only Maerzens. With 1 g/L of sugar the carbonation was perfect; i once got some explosive bottles with higher dose. Unlike the past years, my actual bottles are good quality bottles, but even if they won't explode i still prefer not to paint my house's wall with beer!
Do you think the 5 g/L sugar dose for priming is safe?
May I have the opposite problem, i.e. undercarbonation due to cold-crash and Isinglass? Should i add some carbonation yeast?
Thank you, and sorry if i made some mistakes with English: it's not my mother tongue!

 

[VikeMan]

Assuming the residual CO2 associated with a temperature of 20C, 5 grams of corn sugar per liter would get you 2 Volumes of CO2, which is probably even a bit low for an IPA, and certainly not dangerous.

Are you sure you were using 1 gram per liter before? That would get you about 1.1 volumes of CO2, which is very, very low for most styles.

 

[thehaze]

I can assure you that it is impossible to get proper carbonation with only 1 gram of white sugar for 1 liter of beer, no matter the OG, the recipe, ale/lager, etc.

For any kind of beer, you need around 4.5 grams per liter to get a carbonation level of around 2.0 vol. CO2 which is low for a lot of beer styles. Might be suitable for Imperial Stouts. You need around 6.5 grams to go up to around 2.5 vol. CO2, which is a level that it is used in a vast majority of ales and lagers. Beer, once fermented, it will have a residual CO2 level of around 0.8-1.2 vol- CO2. With one 1 gram of sugar per liter, your beer will only have 1.1 vol. CO2, which is extremely flat beer.

I assume that you don't drink flat beer and the carbonation you got until now, was OK. So that means, those beers you primed with only 1 gram of sugar, never finished fermenting, when you bottled them - they actually finished fermentation in the bottle - where the yeast was most likely awaken and got to work, once the sugar was added.

5 grams per liter is also too low. I've bottled a little over 100 batches and for 2.5 vol. CO2, I always used 6.5 grams per liter. It worked perfectly every time. So I believe, whatever your process was, somewhere, something happened without you knowing. But it is strange, that you got away each time with that 1 gram per liter. That would mean every batch you did, refermented more in the bottle than expected, thus creating carbonation.

 

[dennybc]

Yes, I'm sure, it was 1 g/L. What I'm NOT sure of is if the fermentation was correctly over back then, because it was my dad's beer and fermentator. But i know he used to keep long fermentation time (4-6 weeks). My hypothesis are wrong temperature or wrong sugar distribution during the bottling time, but i can't correctly guess right now.

 

[dennybc]

I can assure you that it is impossible to get proper carbonation with only 1 gram of white sugar for 1 liter of beer, no matter the OG, the recipe, ale/lager, etc.

For any kind of beer, you need around 4.5 grams per liter to get a carbonation level of around 2.0 vol. CO2 which is low for a lot of beer styles. Might be suitable for Imperial Stouts. You need around 6.5 grams to go up to around 2.5 vol. CO2, which is a level that it is used in a vast majority of ales and lagers. Beer, once fermented, it will have a residual CO2 level of around 0.8-1.2 vol- CO2. With one 1 gram of sugar per liter, your beer will only have 1.1 vol. CO2, which is extremely flat beer.

I assume that you don't drink flat beer and the carbonation you got until now, was OK. So that means, those beers you primed with only 1 gram of sugar, never finished fermenting, when you bottled them - they actually finished fermentation in the bottle - where the yeast was most likely awaken and got to work, once the sugar was added.

5 grams per liter is also too low. I've bottled a little over 100 batches and for 2.5 vol. CO2, I always used 6.5 grams per liter. It worked perfectly every time. So I believe, whatever your process was, somewhere, something happened without you knowing. But it is strange, that you got away each time with that 1 gram per liter. That would mean every batch you did, refermented more in the bottle than expected, thus creating carbonation.

My guess is the same as yours. I hope this time the fermentation is over, but I'm pretty sure (right and stable FG), so i think i will use 5-6 g/L.
Do you think on the other side that the remaining yeast after the cold crash is sufficient?

 

[VikeMan]

Do you think on the other side that the remaining yeast after the cold crash is sufficient?

Almost always.

 

[thehaze]

There will be enough yeast to create carbonation, even when the beer was cold crashed for several days. So I wouldn't worry. However, there seems to be some flaws in the brewing process - really, no beer needs 4-6 weeks in the fermenter. If it stayed 4-6 weeks and then eventually refermented in the bottle further, then something about the fermentation temperature and schedule was off. Any beer ( leaving aside Brett, etc. ) would be completely done in 7-14 days.

 

[dennybc]

There will be enough yeast to create carbonation, even when the beer was cold crashed for several days. So I wouldn't worry. However, there seems to be some flaws in the brewing process - really, no beer needs 4-6 weeks in the fermenter. If it stayed 4-6 weeks and then eventually refermented in the bottle further, then something about the fermentation temperature and schedule was off. Any beer ( leaving aside Brett, etc. ) would be completely done in 7-14 days.

I know, but as i said i can't understand now what happened years ago, i can only guess. Regarding this beer, the fermentation started vigorously 8-10 hours after the yeast inoculation (US-05). After a week i siphoned it and i kept it another 2 weeks. Temperature was always between 19 and 24 degrees (C).