Force Carbonating Hard Cider

[Glenn C Keller]

A subtle point about force carbonating hard cider in a keg. Can someone please offer their thoughts?


Whenever I force carbonate hard cider using a 5 gallon KegCo keg and food grade CO2, the cider changes in flavor (not for the good) to produce a bitter aftertaste. During the carbonation forcing and afterwards (for a month or longer) when I let the keg age, I have left the gas on continuously.


I was told that I should be shutting off the gas, and then shaking the keg, and then turning the gas back on to re-pressurize the keg, shaking, and so on, until the gas pressure on the gauge no longer goes down after shaking the keg. Then I should leave the gas off and let it sit for a month and this will produce a nicely carbonated cider with fine bubbles, but without the bitter aftertaste.


Does leaving the gas on change the chemical reaction of producing Carbonic acid that could otherwise be avoided had I left the gas off?

 

[Maylar]

Nope. If anything, carbonation adds a slight perception of sweetness. Could you be tasting keg cleaner or Star San?

 

[mike_57401]

I'd expect carbonation of cider results in carbonic acid, which lowers pH. This would add a bit more tang, or sharpness, or "sweetness" to some tongues. In similar fashion, pH of carbonated water (5.5) is much more acidic than pH of typical tap water (8.0).

As far as whether gas is left on or off, etc: carbonated is carbonated. There are differing levels of carbonation, corresponding to the pressure at which it is carbonated (how many volumes of CO2 in solution). This will alter the taste as well.

Maybe carbonate to a lower level (1.5-2.0 volumes) rather than a higher level(2.5 to 3.0 volumes) if you find that carbonation negatively impacts the taste for you.

 

[Glenn C Keller]

OK, thanks for the clarifications - I will assume that it makes no difference whether or not the gas is left on or not for an extended period of time during the carbonation process. I will try again in a couple weeks when I get back upstate NY. I will be sure to sanitize and rinse out the keg - I use potassium metabisulfite in solution as sanitizer followed by several hot water rinses. I will carbonate at a lower pressure (15 psi instead of the full 30 psi) and leave the gas turned on. I have 4 - 5 gallons of cider with ~ 9% ABV which has been fermented to dryness and has been sitting for a year in a 14 gallon demijohn with a bubbler and a scant 1/2" air gap. I intend to fill up a 5 gallon, keg add a couple tsps of apple flavoring and back sweeten with stevia or erythritol or xylitol to taste, and gently shake the keg until the pressure does not lessen while shaking and then let it sit for a few weeks in a cool cellar.

Can someone recommend a liquid pH tester? There are several on Amazon (phPerfect kit, …) but not sure if these are only for water. It would be good to know the pH before and after carbonating to see how much effect the carbonation has on reducing the pH.

 

[Maylar]

Can someone recommend a liquid pH tester? There are several on Amazon (phPerfect kit, …) but not sure if these are only for water. It would be good to know the pH before and after carbonating to see how much effect the carbonation has on reducing the pH.

I had one of those cheap Chinese pH meters (yellow) and had nothing but trouble with it. It wouldn't give the same reading twice in a row. Ended up with a Milwaukee MW102 and I'm very happy with it.

 

[mike_57401]

I'd be curious to find out the results of your pH testing.