Some of my bottles usually turn out over carbonated, and some turn out under carbonated. Is there a good technique to get consistent carbonation? I imagine it is a function of both evenly distributed priming sugar and also the yeast. The latter might be more difficult to achieve since it settles a bit during bottling?
- weigh your priming sugar, don't measure the volume
- boil it in just enough water to dissolve it for a few minutes
- pour that sugar syrup into your bottling bucket
- rack the beer onto the sugar mixture
- give it a couple gentle stirs with a sanitized spoon
That works for me. Hopefully it will work for you, too!
The yeast that carbonates your beer should already be in suspension, that is, invisible without a microscope. So, unless you've filtered the beer, don't worry about the yeast. Don't stir up the yeast cake either, those might not be very happy/tasty.
But, you should stir the sugar into the beer to get good carbonation, as discussed here and in many other questions. I gently stir several times with my sanitized racking cane, to get most of the beer visibly turning, before I slowly add my sugar. Works quite well and if a bit of the yeast cake gets picked up it seems to drop right out again.
Other other hand, if you do need to add a yeast for conditioning, just stir it into the beer as you would with the sugar.
Rack your beer out of the fermenter into a sanitised bottling bucket, which could just be another fermenter, where the beer is evenly mixed with all your priming sugar before being bottled straight from there.
Normally the under / over carbonation issue is caused by differing amounts of priming sugar added to each bottle when priming the bottle individually. This extra stage ensures even distribution of priming sugar and yeast throughout the batch so the bottles are much more consistent.
Before I switched to kegs, the easiest and most reliable method I found was to siphon off some of the beer (typically a litre or so), warm it in a saucepan, and dissolve the appropriate amount of priming sugar. I used dextrose or some other invert sugar since it seems more likely to ferment out thoroughly, and less likely to impart off flavors.
Of course I let the priming liquid cool before gently stirring it back into the main batch.
[ edit: Oops, I just noticed Denny Conn beat me by about 8 minutes. I'll let this stand for whatever it's worth. ]
I have had the same problem, quite a few times. Different bottles haveing different levels of bubbling. I think it could come down to the 'conditioning', be careful to adhere to the guidlines for each type of beer, once in the bottles a lot of different science comes into play, light, temperature, vibration, and time all need to be carefully managed. Light being key to my problem at first. The yeasts need time to eat the priming sugar and give the right mix of bubbles and head, so if i get a brew which is clear yet a bit dead i just give it some more time to sort itself out. In the end , it is your creation, a beer, and it is what it is, try not to compare it to others and enjoy it for what it is.
There is a chart that provides this info. I use sugar cubes for consistency. http://www.google.com/imgres?imgurl=http://www.kegoutlet.com/media/uploads_ckeditor/Carbonatin-Chart.jpg&imgrefurl=http://www.kegoutlet.com/keg-carbonation-chart.html&h=741&w=960&tbnid=MlpE8A_fRys_XM:&zoom=1&docid=2lDqdYiB4YtYLM&ei=74sTVa7FD4uyogSN3YGYDA&tbm=isch&client=ms-android-hms-tmobile-us&ved=0CB0QMygAMAA