Hard Cider Tip #12: Counter-Pressure Bottle Filling

As a homemade hard cider maker, I keep finding myself looking for new and maybe better ways to make and process my hard cider. Most of my hard cider recipes are based on my current method for making hard cider, which entails using kegs. Kegs have given me more flexibility in managing my process for making hard cider. My hard cider recipes could all easily be converted to other methods. For example, you can bottle condition instead of force-carbonating. You can also age or fine hard ciders instead of filtering. One process isn’t right or wrong, though the process can impact the final results of your hard cider.

I moved to kegs because I wanted a cleaner cider. I found most people drinking my hard ciders preferred clear hard ciders with some level of carbonation. Bottle conditioning, even with yeast like CBC-1, would still leave some residual lees that would cloud the hard cider. I also found that I was always having to manage headspace issues. Kegs solved many of these challenges but to realize the full benefit, I also needed a counter-pressure bottle filler. Check out The Shop Page if you are interested in ordering kegs or the counter-pressure bottle system that I use.

Carbonation or effervescence is the suspension of carbon dioxide (CO2) in hard cider. A counter-pressure bottle filler works to minimize the loss of carbon dioxide (CO2) that is suspended in your hard cider (i.e. foaming) during the bottling process. We will troubleshoot potential causes for foaming later in this article, but let’s cover a little of the science behind carbonation and how a counter-pressure filler works.

Yeast, which consume sugar to reproduce, create alcohol and CO2 as by-products of their reproduction process. Forcing or keeping that CO2 suspended in hard cider is what makes a hard cider bubbly or effervescent. For example, when your hard cider has finished its primary ferment, atmospheric pressure at room temperature (70F) will normally keep around 0.85 volumes of CO2 suspended in your cider. There are two key things helping to keep CO2 suspended in hard cider: temperature and pressure.

The colder your hard cider is, the more CO2 it will absorb and keep suspended. The higher the pressure is in the vessel your hard cider is sitting, the more CO2 your hard cider will absorb and keep suspended. These two elements, temperature and pressure, form the basis of carbonating your hard cider. The goal of a counter-pressure bottle filler is to help you keep it suspended while you are bottling.

A counter-pressure bottle filler is different from a bottling wand or tube because it pressurizes the bottle you are filling. Remember, pressure helps to retain CO2. Your keg is pressurized, which is how you forced or retained the CO2 in your hard cider. Moving your hard cider from one pressurized container to another means less CO2 is released. You might be wondering how it can move the hard cider if both containers are pressurized. The pressure in the bottle is a little lower. This is managed by a leakage valve that you set. The amount of leakage sets the rate that the hard cider flows into the bottle as well as helps to control how much CO2 is lost through foaming. The slower the transfer, the smaller the leak, the less CO2 will come out of suspension.

Here’s a video walking you through the setup and use of the counter-pressure bottle filler system. This will give you the fundamentals of the bottling process. If you are having issues, check out some troubleshooting tips at the bottom of this post.

The most common issue with bottle filling systems is foam. Have you ever tapped a keg and just gotten foam? There are multiple reason this could happen. Let’s troubleshoot some of the top potential causes.

• Over-Pressurized Keg: I’ve found the counter-pressure bottle filler systems available for small craft hard cider makers don’t really work when the keg pressure is above 15 PSI and are best when it’s below 10 PSI. If you have 20 PSI in your keg when you try to start filling, you won’t be able to use the filler effectively. You will blow the seal out of the bottle and ultimately, your keg pressure will drop. Guess what starts happening to the CO2 suspended in your hard cider sitting in your keg when the pressure in the keg drops? It starts coming out of suspension before it even gets into your bottle. You get foam. You should try to force-carbonate so your keg is 10 PSI or less. Use a force-carbonation chart to find the temperatures and pressure for the CO2 volume you desire. You can find them on the internet or in my book In the carbonation section. For example, 10 PSI at a refrigerator temperature of 40F will give you just over 2.25 volumes of CO2, which is just below sparkling. 20 PSI at 40F would be 3.25 volumes. That would definitely be sparkling and may be excessive for some bottles.
  
• Filling too Fast: The rate you fill is a reflection of how much your pressure differential is between the pressure in the keg and the pressure in the bottle. If you don’t open the leakage valve, they are the same and no hard cider flows into the bottle. If you open the leakage valve too much, the pressure differential is greater and the hard cider flows faster. The higher the pressure differential is, the more CO2 will be released because higher pressure keeps it suspended. You have to balance the flow rate of the hard cider with the amount of foaming your are getting. Slow the flow to decrease the foaming by closing the leakage valve.
  
• Warming Temperature: If you are bottling a large batch, the keg is going to warm as you process it. Also, if you are putting the hard cider into warm bottles, the cider will warm as you bottle it. You want to keep everything as cold as possible. Bottling in the bright sunshine isn’t recommended. If your keg warms, it will be releasing CO2 even before it leaves the keg. If your bottles warm, it will be foaming in the bottle. An ideal situation is to force-carbonate to your desired CO2 volumes and then stick your keg someplace colder. This allows you to use the pressure in your CO2 tank to move the hard cider and keep more of your CO2 suspended.

Remember, you can find other tips under the tips section or in my book.

If you need some hard cider recipes or ideas for making your own hard cider, check out my recipes sections. As always, thanks for reading.

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