How to troubleshoot flat beer?

Question

Since I started brewing in January, every single batch (6 so far) has come out flat. I've had a couple come good after a few months in the back of the garage but for the most part, it's all flat.

At first I was underfilling the bottles quite significantly but I've since begun using a bottling wand & filling to overflow and the results are the same.

I've been giving the partial-wort (I've been doing partial boil extract brews) a good shake & have always poured from a height. Is that enough aeration?

All brews have been fairly standard alcohol levels (highest at 5.1%) so I don't think it's that.

My glasses do come from the dishwasher but they handle commercial beer fine. The beer itself just doesn't have a steady flow of bubbles.

I get plenty of sediment sitting on the bottom of the bottles so I think it's conditioned enough (I usually wait 2 weeks minimum before opening).

What approach should I take to trying to find the source of my problem? Are there a few likely culprits I can try & experiment with small batches? Are there any tests I can do? Worst case scenario I'll have to invest in a keg setup (darn).

Answer 1

I haven't bottled for a while now, so this is just some thoughts. Others, I am sure, will have helpful advice.

My first thought is that you are under-priming. Make sure you are adding the right amount of priming sugar. Too much and you risk a blow-out, too little and low carbonation. I can't recall the best quantity at the moment but if you can add it to the bulk before bottling you should get an even mix. I would leave a small airspace above the beer in the bottle, perhaps no more than an inch (2.5cm). This should allow enough build up of head pressure to achieve good carbonation.

Are you leaving the bottles in a warm environment (70 degrees) for a week or so before transferring to a cooler place? This will allow the yeast to ferment the priming sugar and produce your conditioning gas.

I am not sure I understood what you meant by:

I've been giving the partial-wort (I've been doing partial boil extract brews) a good shake & have always poured from a height. Is that enough aeration?

Do you mean prior to fermentation or after? Once fermentation is complete, I would avoid aerating the beer at all, as any introduction of air is going to encourage nasties. You did mention you use a bottling wand and this should be immersed as you fill.

Lastly, are you, perhaps, expecting to see find as much gas as commercially filtered and carbonated beer. I never found my bottle conditioned beer to be as gassy as brewery conditioned beer - in fact I prefer it not to be. My preference is for bottle conditioned beer to have life on the tongue but not to be 'fizzy'.

Hope some of this helps.

Answer 2

Priming sugar at bottling time and 70F temps during carbonating are the likely culprits. How you treat the wort preferment (partial boil and aeration techniques) has little to do with carbonation issues.