Originally Posted by aboatella
Thanks for taking the time to answer. I think I am a little bit confused between the fact of having CO2 in solution and fermentation itself. Why do we need to prime the solution before bottling if we already have co2 in the solution? Sorry, I have many doubts about this.
Well, co2 is a byproduct of the fermentatiion process. Actually Alcohol AND Co2 are the byproducts of the fermentation process. Co2 is always present to one degree or another in fermentation. When our beer is in the fermenter it, besides showing up as little bubbles in your hydromter jar, is forms a protective cushion around you beer, especially on the surface in your fermenter, keeping oxygen and particulate matter out of your beer. When there is too much it goes out the airlock, which is a valve to keep from painting the ceiling with your beer. You can often see the bubbles in the small amount of water or whatever you put in your airlock.
To carbonate your beer, we harness that co2, and we add more sugar to produce more co2.
The yeast eat the sugar solution you feed them. They "fart" co2. The CO2 fills the headspace in the bottle FIRST (the one to one and a half inch dead space between the beer and the cap) CO2 keeps being generated,and it maxes out the headspace. So it has a couple choices...blow the top of the bottle (the cap) Blow up the bottle, or seek the path of least resistance and dive back into the beer, and get absorbed (carbonated) by the liquid. Since the cap is pretty tight (and ingenious in it's design) and most bottles don't have any flaws and can maintain the pressure, the gas more often than not, takes the third option and goes back into the liquid and is FULLY absorbed by it.
The amount you add to your beer at bottling time actually factors in the amount of co2 present already from fermentation. We usually don't bother with figuring it out until we get into something called "carbing to style" then the temp of the beer at it's highest point comes into play, because the colder the liquid the more co2 it holds. So for example if you beer were cold at bottling time, and you were using a bottle carbing calculator in software and you happened to type in the temp of your beer it would show you'd need a lot less sugar to get the same level of carbonation had you carbonated it at bottling time. But you can look into all that later. In the beginning just know that the 4.5-5 ounces of priming sugar that came with your kit or is called for in your recipe is the perfect amount for what you need right now, at this stage of your brewing career.
Most fermentation vessels are not strong enough to handle that forcing the co2 into solution, our lids or bungs blow off first. However that is pretty how a keg is carbonated, either naturally with sugar OR forced with co2, but a keg is a high pressure vessel that can take the co2, prevent it from venting and force it into solution.
You could conceivable ferment and carbonate in the same keg, BUT if you look at how nasty your fermenter is when you rack the beer to a secondary or bottling bucket, you see how much crap would be in your beer if you just let it all happen at the same time.
So, as you can see, there's a fine line between being "fizzy" and being truly carbonated. Just tasting your hydro sample as compared to a fully carbonated beer should give you an idea of the difference.
This video by Poindexter from here, illustrates the carbonation process that occurs in the 3 weeks minimum we talk about a beer needing to fully carb.
But this subtle amount of co2 that you experienced can start to form the minute yeast and sugar meet. It's just like us having beer and chilli, we're going to pee and fart as well....Only for us the chemicals we put out aren't simply Ethoh and Co2, but more complex things, including methane, and god knows what all in our urine.
This is pretty common in winemaking, folks talk about constantly needing to "degass" their wine...for us with beer we keep it around during fermentation and add more to carbonate the beer, but since wine is still, the do all sorts of things to get rid of the excess co2 including doing this to it.
They run that for a few minutes or so to break up the co2 in the solution.
After reading your reply I think what I'll do is wait a few more days and then bottle.
I'd leave it for a month, your beer will thank you for your patience.
One last question, to have an accurate gravity reading, should I wait for the co2 to disapear? As I said the co2 pushes the hidrometer up and the reading is different from the one when most co2 is gone.
All you need to do is tap the side of your hydrometer test vessel a few times to dislodge your bubbles. That's the same thing as "degassing" as mentioned earlier. But a few bubbles don't really thorough off the gravity reading that much. they hydrometer is still a pretty heavy thing. It need to be as carbonated as a fully carbed beer to throw off the hydrometer, that's why we don't traditionally take a hydro reading of the bottle conditioned beer.
but the microscopic amount of psi in a fermenting beer sample usually isn't enough to through off your reading. And a couple of taps of the hydrometer tube, or spinning the hydrometer is usually enough to degass it.
Bottom line relax....you have new brewers nerves...Your beer is fine. And will be better in a few more weeks.