Flat beer

[rpt]

The last couple of brews I have bottled have been flat (although there has been a psst when I opened them and there is a little life in the beer). I can think of a couple of reasons this might have happened.

1. Previous brews have been made in colder weather. Once the bottles have been in the house for a couple of weeks to carb up I put them in the garage. At the moment it is around 20C whereas earlier in the year it was more like 4-10C. So perhaps the CO2 just hasn't been absorbed into the beer. However, one of the brews did spend a week in the fridge at 2C and it is still flat.

2. I batch prime. I put 100g of sucrose in 200mL of boiling water and boil for 15 minutes. I let it cool down before pouring the sugar syrup into the bottling bucket and then syphon the beer on top. I'm wondering if I'm losing a lot of water during this boil making the syrup quite thick. I then leave it for quite a long time to cool so perhaps some sugar is dropping out of solution and so when I pour the syrup into the bucket I'm not getting as much sugar as I need.

I do use some PET bottles and these have gone firm but not as firm as some other beers I have so that does suggest 2 is the reason, although I have done the same with other brews.

Any thoughts?

 

[mattrickl06]

Kits or AG?
23l brewlength?
Bitter or Lager?

 

[morethanworts]

It's a strange one I guess because you're not a newb! I can only guess it's option 1 and/or more time, if your testers are pumped up and assuming you are using the same serving temperatures (and even glasses/detergents) as before. I don't imagine these things would present your beer as 'flat' though.

I had beer in a PB this spring/summer which seemed to have plenty of pressure from priming (I didn't add gas until maybe 3/4 way to empty) but never got remotely carbonated, even though bottles I had at similar (relatively high) temperatures did. It's a mystical art (or just a frustratingly complex science) sometimes.

I've only just acquired a brewing fridge and I'll be interested to see what difference it makes to the timescale of CO2 absorption after the warm period following priming.

 

[rpt]

Kits or AG?
23l brewlength?
Bitter or Lager?

AG. Different brewlengths but always prime at a rate of 100g sucrose per 23L. These are all ales. The brew before that was lager and I primed with 120g sucrose for 23L. This is very nicely fizzy. The one before that was an ale but I only primed with 80g. It is fizzier than my recent two but slightly less fizzy than I would like - not surprising since I used 20% less sugar.

 

[orlando]

Not 2, unless you don't stir properly. At 100g you certainly have enough sugar. I once had a beer poorly carbonate and knew immediately why that happened as I remembered tasting the beer left behind that didn't go into the bottle was sweet; I hadn't stirred after adding it to the bottling bucket, I assumed that just putting the beer onto it would agitate it enough. I was of course worried about stirring too much and introducing oxygen. A proper period of warm conditioning followed by cold conditioning should do it.

 

[mattrickl06]

Kits or AG?
23l brewlength?
Bitter or Lager?

AG. Different brewlengths but always prime at a rate of 100g sucrose per 23L. These are all ales. The brew before that was lager and I primed with 120g sucrose for 23L. This is very nicely fizzy. The one before that was an ale but I only primed with 80g. It is fizzier than my recent two but slightly less fizzy than I would like - not surprising since I used 20% less sugar.

Hmm - sounds strange, the only time that i have had flat beer was when i added two whirlfloc tablets at the end of the boil by mistake - do you use irish moss or whirlfloc tabs? if so how much?

 

[rpt]

I use 3g Irish moss at the end of the boil. The plastic bottles do go hard so there is definitely some yeast and sugar working.

 

[rpt]

I think I understand what is happening here thanks to a worrying incident this evening. As I opened a bottle of oatmeal stout the top of the bottle exploded sending glass flying and producing a very impressive fountain of black beer from the kitchen worktop to the ceiling, particularly as our kitchen ceiling is quite high. Fortunately I only had superficial cuts but cleaning up the mess wasn't the most fun way to spend a Friday evening.

This was the very last bottle of this batch so came from the bottom of the bottling bucket. The sugar wasn't properly mixed in - most bottles were flat because most of the priming sugar was in this one bottle. I won't rely on the priming sugar mixing in just by syphoning in the beer on top in future.

This also shows that getting firm plastic bottles is no proof the beer is properly carbonated.

 

[nobyipa]

always batch prime results are random between 80 and when brave 130 grams per 23 litres boiled in 100ml to 150 ml water
i on average use 100 grams per 23 litres but never venture past 130 grams per 23 litres I only boil it for 3 to 4 minutes i do not reduce it
if i want ice cream head only occasionally i use 130 for the laugh but its hard to get out of the bottle.

hers an ipa with 130 grams.

as a matter of course for me
i wait for the priming solution to cool to 18c in a cooling bath.
carefully pour in the priming solution and then stir the wort into a fast"ish vortex no air with me big spoon

then av a beer and wait for it to evenly distribute through the wort.
about half an hour.
Cheers

 

[daf]

Both sets of lager I bottled after batch priming were flat, while all bottle primed ones were perfect.

Lessons learned.

 

[PD]

I'm a recent convert to batch priming. Bottle priming was always good and the bottles always had the required amont of fizz.
However its a slow time consuming process, so I moved on to bulk priming.
Its taken a while to get to the same level of consistency of fizz
alterations I've made include making the bulk priming sugar with cooled boiled water before its required, adding the beer to it and giving it a gentle " good " stir.
The bottles then have to be kept in a good warm place ( my airing cupboard is great ) for at least 2 weeks 3 if possible. That ensures the yeast can get stuck into all the sugar and make plenty of gas.
This gas is mainly sitting above the beer in the void and it needs to be forced into the beer, this I do by cooling the bottles for a further 2 or 3 weeks. and I mean cool ( not freezing obviously) but cold....
Its long winded I know but I've found it works well for me.
My corny's are also cooled before adding the gas and for a good week or more after gassing to allow the gas to get INTO the beer, not sit on the top of it

Hope the above is of help to you.....

 

[KIWI]

Hi there for what its worth I batch prime 130g for 23 litres i have found this amount fine, I dont stir just add to boiling water then let it cool and chuck in then give it a wee shake.
I have been using dextrose so I need a bit more because it is very fine sugar.
I then leave it in the fermenter for a good time while I am getting ready to bottle with the heat on.
then secoundary ferment for three to four days or more, it is worth the wait.

then I cold condition depending on the style.
never had a flat beer yet.

Cheers.