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5 gallon Corny kegs in temperature-controlled freezer
5 gallon Corny kegs in temperature-controlled freezer

Carbonating your homebrew

Do you have problems getting the right levels of carbonation in your homebrewed beer? Do you bottle condition and find that sometimes your beer is flat or under carbonated or becomes over carbonated? Do you force carbonate your beer and find that it foams too much so you feel like you waste more than actually ends up in bottles?

I have been homebrewing now for 4 years and have encountered all of the above problems so thought it was time for me to share my troubles and try find out some answers to these commonly encountered problems.

Bottle Conditioning

Bottling beer with a Bench Bottle Capper
Bottling beer with a Bench Bottle Capper

As with most people who are new to homebrewing I started with extract and mini-mash 5 gallon batches then once the primary fermentation was complete I would rack the beer into carboys and leave them to settle and clear plus any final fermentation to finish off. Once ready I would siphon the beer into a bottling bucket and add 4oz of corn sugar that had been boiled in 2 cups of water and allowed to cool.

Once the priming sugar had been gently mixed into the beer to avoid introducing oxygen I would then use a filling wand on the end of a tube and straight cane to fill and then cap the cleaned and sanitized bottles. After storing the beer at 65-70 degrees F for two weeks I would have properly carbonated been – voila, nice and easy!

I always tended to find that although these beers were reasonably good they always had that extract edge to them whether I used fresh Liquid (LME) or Dried Malt Extract (DME) so after 6-8 batches it was time to move to all-grain and so the challenges began…

Flat, Under or Over Carbonated Beer

Brewing Classic Styles
Brewing Classic Styles

After moving to all-grain brewing I started to find that the carbonation levels of my bottle conditioned beers started to vary. Sometimes after 2-3 weeks the beer would have minimal carbonation and might take a month or more to get the desired level of effervescence. Other times the beer would be carbonated in 10 days but by the time the beer was a month old the carbonation would be excessive and in the worst cases turn into fountains upon opening – aka potential ‘bottle bombs’.

I then came across a table in Brewing Classic Styles by Jamil Zainasheff and John Palmer called ‘Nomograph For Determining Amount Of Priming Sugar (by Wt.) For 5 US Gallons’.

This table comprises of three columns:

  • Temperature – going from 32 deg F at the top down to 75 deg F
  • Volumes of CO2 – going from 4.5 at the top down to 1.5
  • Corn Sugar & Cane Sugar – going from 9 & 8.5 oz at the top respectively down to 1 oz for both
Priming Sugar Nomograph
Priming Sugar Nomograph

The idea of this table is that you find out the number of volumes of CO2 you want in your beer based on style e.g. 2 for a Stout, 3 for a Pale Ale, 4 for a Belgian Blond then based on the temperature at which the beer is primed you can line up the first two columns and the amount of priming sugar for that temperature and CO2 volumes will be shown in the third column.

The example in the photo shows that at 65 deg F to get 3.0 volumes of CO2 you would need to prime with 5 oz of Corn Sugar. This amount could be doubled to 10 oz if priming a 10 gallon batch.

So how did this turn out? Well sometimes it was fine but other times I still encountered problems with under or over carbonation. It could not be that the table is wrong as Jamil is one of the most decorated homebrewers in the USA and now runs his own brewery and John is a leading author on homebrewing plus provides consultancy to brewers as well as gives talks in brewing around the world so it had to be that either I was still doing something wrong and/or there was something else going on here…

After listing to a lot of homebrew podcasts and reading up on the subject I suspect that two things could be happening:

  1. Mashing temperature – one issue I have always encountered is trying to maintain a consistent temperature in the mash. Originally I brewed on the stove top and mashed in an 8 gallon pot then I migrated to a 3-tier keggle system using converted 15.5 gallon Sanke kegs with propane as the heat source. With the latter I have tended to find that either the kegs store heat from the burner and the mash temperature can overshoot by a few degrees or if just left (even with insulation) the temperature can fall but bringing it back up can lead to overshooting again. The result I believe can lead to too many complex sugars when mashing too high that somehow eventually do get eaten by the yeast when in the bottle and lead to over-carbonation. What leads me to this conclusion is that some beers such as my Stouts have a too higher Final Gravity (FG) and taste a bit sweet but once left for 3-4 months can end up over carbonated but taste much better and not so sweet.
  2. Yeast – another problem which I suspect may contribute to problems in getting sufficient carbonation is not enough healthy yeast being in the bottle after fermentation has finished. Some people suggest adding extra yeast to the bottling bucket but I find that rarely do I have a spare vile or sachet of yeast. If this is the source of the problem with under-carbonation then perhaps I need to get an extra sachet or vile of yeast per batch but right now I am not wholly convinced this is the problem and suspect it is more to do with #1 above. I have just invested in an Electric Brewing system (see the series of five articles on this here) and ‘believe’ the control and recirculation should address the mash temperature issue. If this does not resolve bottle conditioning issues then additional yeast at bottling time will be the next solution to try.

Forced Carbonation and Kegging

CO2 tank
CO2 tank

Many people have said kegging is the way to go as bottling is labor intensive – this I have to agree with as the de-labelling of bottles, washing them and then sanitizing is arduous to say the least and incredibly time consuming BUT with being a weekend-only drinker and someone who likes to share their beer plus vary what I enjoy a 5 gallon keg of the same beer at a time does not appeal.

I was fortunate enough to get the opportunity to buy 4 used Corny kegs with spare seals at a bargain price from a fellow homebrewer who was moving States and wanted to slim down his homebrew equipment. This combined with an online sale to secure a 20Lb CO2 tank plus regulator and fittings allowed me to get a kegging system for a somewhat reasonable price. My thought was that I could control the carbonation levels of the beer and remove the element of chance that comes with bottle conditioning.

So how has this worked out so far being one batch into force carbonating beer and bottling it? Well let’s just say that I need to do some more research as there are plenty of creases that need ironing out.

Brewing better Beer

My first question was how do I get the beer carbonated? I turned to Brewing better Beer by Gordon Strong whom I have met on a couple of occasions and respect highly as the only three times Ninkasi Award winner. In his book he suggests chilling the keg of beer, which I did to around 36 deg F, and then putting 30 Psi of pressure into it and shaking so that the CO2 dissolves into the beer. This I did twice on day 1 then the next morning sampled it and thinking the carbonation was a bit low I repeated the exercise for another day.

I poured some of the Brown Ale at a homebrew meet and it was properly carbonated and with an almost nitro creamy texture that tasted great! I had already dropped the pressure in the kegs to 10 Psi which seems to be serving pressure that many people use.

Bottling with a counter-pressure filler

Blichmann Beergun counter-pressure filler
Blichmann Beergun counter-pressure filler

In addition to the kegging equipment I also invested in a Blichmann Beergun with accessory kit (approx $100) which I have heard many people rave about. I read the instructions and watched a video demonstrating how to use it.

After cleaning and sanitizing a batch of bottles I got the keg out of the temperature-controlled freezer and attached it to the CO2. I had also chilled down the bottles as warm ones can increase foaming. I connected the Beergun to the CO2 and the beer line to the Out ball socket on the Corny keg. The regulator was set to 5 Psi which should be right for pushing out the beer without causing foaming from being too high.

As per the instructions I purged each bottle with CO2 for 4-5 seconds then pressed the trigger to start filling the 22oz bomber bottles from the bottom and at an angle… and so the foaming challenges started!

5 gallon Corny kegs in temperature-controlled freezer
5 gallon Corny kegs in temperature-controlled freezer

There seemed to be a range of things going on here:

  1. Air bubbles were coming up the beer line from the keg which confused me as the beer comes out of the keg from the dip tube that goes down to the bottom. Perhaps there is a problem with the Out poppet ball-lock post allowing CO2 from the head space in the keg to get into the beer as it exits the keg? Maybe the beer is over carbonated and contains too much CO2 that then starts to come out of solution when leaving the cold keg and entering the warmer beer line and bottle?
  2. Between filling each bottle the beer would go partly back down the beer line so that when filling the next bottle air or CO2 is pushed into the bottle and causes foaming? In theory if there is enough pressure in the keg then the beer should not do this in the line?
  3. Sometimes when finishing filling a bottle there would be a rush of bubbles coming from the bottom of the bottle that would cause it to foam and become under-filled. Eventually I found out that this was down to CO2 coming from the CO2 line so perhaps my finger was catching the purging button?

I know there are some things to work on concerning the above and plenty more reading that needs to be done in order to fine tune the force carbonating of beer and subsequent filling with the Beergun but if anyone has recommendations or thoughts on how best to address some of the issues raised in this article then I would be very grateful to hear from you and urge you to contribute by leaving your comments below.

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