Beware The Perils of Bottling! May 17, 2016 16:23

So, you made some beer. Excellent! Maybe you just want to enjoy it at home; maybe you want to share it with friends or serve it at a party; maybe you even want to enter it into a competition. All are good choices. The question is how to best accomplish these goals. Kegs work well for the first two, but you generally shouldn’t be entering competitions with a full keg. They are hard to mail after all.

At some point in your brewing life, you will have to put beer into bottles. Most homebrewers start there, and there is no shame in bottling. Some people even think it is the most fun part of the process. Well, the second most fun part. As in all things, however, if you are going to bottle your beer, you might as well do it right. Especially if you are entering a competition.

Proper bottling technique ensures your brew will reach its fullest potential. Carbonation is important for most styles, and generally critical to the palate of most consumers. While terms like “fizzy” are often used as pejoratives, those tiny bubbles are important to the beer experience. They aid aroma, mouthfeel, and flavor. Don’t believe it? Drink flat beer. (Again - this works for some styles or palates, but we don’t all like English cask ales. And certainly not all the time.) Or drink over-carbonated beer and watch it foam all the way out of your glass. The ultimate irony is that either way it ends up flat.

Here are some general thoughts, tips, and recommendations on ensuring properly filled bottles and properly carbonated beer!

Bottle Conditioning:

In short, this is the fancy name for adding sugar to beer and allowing it to carbonate inside a sealed glass container. This process is the slowest and most labor-intensive way to bottle. However, if done properly, it is the most affordable way to create a consistent product. Generally, use 1oz. of priming sugar (we sell dextrose) per gallon of beer. Dissolve the sugar in boiling water - about a pint - and add it as you rack before bottling. You can alternatively use appropriately-sized carbonation tablets, which are a blend of malt extract and dextrose - just fill each bottle and drop them in before capping!

Bottling from a Keg:

There are two ways to fill bottles from a keg: the right way and the wrong way. For temporary purposes, you can fill growlers or bottles that you will drink within 24 hours with either a growler filler attachment off a faucet, or with a bottling wand and picnic tap. These latter methods, even when executed perfectly, will not result in proper carbonation indefinitely. The right way to fill bottles from a keg is with a counter-pressure filler - a tool that purges the bottle with CO2, then fills the bottle with minimal foam and thus minimal carbonation loss! This is the best, and truly the only, way to fill a bottle from a keg if you want carbonated beer many days down the road. This is especially true if you are entering a competition, though you should be sure you are using the tool correctly in this case as improper use will still result in flat beer.

A few pro-tips might come in handy with a counter-pressure filler:

  • You should slightly over-carbonate your keg as bottling will result in some loss of carbonation
  • It is best to chill your filler, tubing, and bottles prior to filling to minimize CO2 losses
  • It is a fair amount of work to bottle a small amount of beer
  • This procedure requires a keg set-up and the equipment is an investment

Now that we have covered how to fill your bottles, let’s move to the trouble with over or under-filing your bottles:


  • Over-filled bottles do not carbonate as quickly or as completely as properly filled bottles! This is somewhat counter-intuitive, but when bottle conditioning, over-filled bottles will either take longer to carb or will simply never carbonate. The jury is out on why this is, though some speculate it has to do with the CO2 being unable to reach equilibrium in the reduced headspace. Whatever the cause, personal experience suggests this is correct.
  • Again, the result of over-filling is low carbonation, which mean your beer loses much of its aroma, flavor, and mouthfeel. And unless this is the intent, the end user does not experience the beer to the fullest extent possible.
  • Finally, over-filling with a counter-pressure filler serves no real purpose. If anything, it can catch an unwary drinker by surprise and result in spilled beer. Using a growler filler or some other method to fill off a keg will result in lost carbonation even if bottle is over-filled


  • Inside the bottle, this means more surface area and more oxygen, which results in a higher risk of oxidation. If you have never tasted oxidized beer, consider yourself fortunate.
  • Infection in the bottle is also more likely.
  • In a logical corollary to over-filling when bottle conditioning your beer, under-filling can result in excess levels of carbonation. This will at best mean foamy beer, and at worst mean bottle bombs. When using a counter-pressure filler or otherwise filling from a keg, under-filled bottles will go flat almost immediately.

Did I mention already that you should be extra sure your bottling process is top notch when entering a competition? Cause that is important. Even if it ultimately has no other effect on the flavor, aroma, or mouthfeel, - which it will, I promise you - judges will still take note of the fill level and judge you on it. I joke a lot, but this is the real deal. In the recent Maine Homebrewers Competition, one of the major recurring problems was improperly filled bottles. In many cases, the judges were reluctant to even score a beer because they were not confident they got the complete picture of the entry. Consider this your behind-the-scenes tip for next year!

*Feel like it is time to get yourself a counter-pressure filler? Mention this blog at time of purchase (you can use the Notes section when buying online) and we’ll give you 10% back in store credit!*