Finished wine in carboy and still has gas.

[sour_grapes]

Tenbears, I would say you have a lot right, along with a few misconceptions. Let me explain.

Are you serious? An exothermic reaction is a chemical or physical reaction that releases heat. It gives out energy to its surroundings. The energy needed for the reaction to occur is less that the energy it creates Where would the chemical reaction be? What chemicals are at work in this situation. What would be the physical reaction be? What energy is produced? The warming of wine is via convection and most certainly NOT by exothermic reaction.

The "reaction" is due to the weak Van der Waals interaction between CO2 molecules and water molecules. This is the interaction that provides any driving force at all for the CO2 to be attracted to other molecules. But this is very weak; we are talking about meV (millielectron volts), not the eV (electron volts) scale characteristic of, say, covalent bonds.

You are certainly correct that the warming being discussed is not due to this exothermic reaction. (I am not sure that anyone actually asserted this.)

Due to this interaction, there is a slight propensity for the CO2 to be dissolved in water, rather than immediately being released. Thermal agitation provides enough energy to overcome this weak bonding, and to facilitate the CO2 leaving the wine. Because there are many more ways for the CO2 molecule NOT to be in the wine, the CO2 will leave until Henry's Law is satisfied.

(To help think about this, think about "dissolving" an H2O molecule in water; it has an attraction to other H2O molecules, which is why water is a liquid at room temperature. However, you may have noticed that water will evaporate at temperatures less than the boiling point. If air above the water is dry, there are many more ways for the H2O molecules to be in the air than in the water, so they preferentially evaporate until Henry's Law is satisfied, i.e., until the relative humidity is 100%.)

Since the Co2 in the wine is introduced to it through an non atmospheric driving force it's partial pressure is not in equilibrium with atmospheric pressure but rather that of the driving force of its origin, (The fermentation process.)

This is absolutely correct, and an important point. Henry's Law only describes the equilibrium situation.

and is contained within the liquid in solution by atmospheric pressure, and the pressure exerted by the medium

But the statement above is a misconception. As I said above, the CO2 is held in the wine by the weak positive interaction with the water. It will leave the water, due to thermal agitation, until it is in equilibrium with the partial pressure of CO2 in the air above the water. It may take a long time to reach this equilibrium.

As the temperatures are reduced the molecules are constricted, creating a denser medium. The increased density of the medium has an inherent tendency to hold gas in solution because it has a sort of squeezing effect on the gas. Inversely as temperature increases nucleic action increases resulting in expansions of the molecules, creating a for lack of a better term looser medium. this decreased density allows, and in some cases forces the gas out of solution.

This is a misconception. Let me cite one fact that should allow you to see that your mental model of this process cannot explain all observed processes. The density of water is a maximum at 39F. As you cool water below 39F, it becomes less dense, i.e., it expands. And yet, the solubility of CO2 does not decrease under these circumstances; in fact, it increases.

Over a period of time the CO2 in solution within the wine dissipates in accordance with Henry's law since the air above it contains less than 1/10 of 1% co2 then the co2 in solution within that wine will be approximately 1/10 of 1%.

That is correct. You got that part totally correct.

 

[Tenbears]

Now to address how the volume effect saturation. Gas is held in solution by pressure, Atmospheric pressure, plus the pressure exerted by the weight of the liquid. During the degassing process the gas in solution is greater where the pressure is greater. There is less gas in solution near the surface than in the lower portion. The lower in the column the more gas can remain in solution. At sea level atmospheric pressure is considered to be 14.7psi. Now, I know that is not absolute, however to save someone from pointing that out I will stipulate to that. Simply for the sake of this discussion we will use the 14.7 figure.
Since Co2 makes up less than 1/10 of 1% of the air surrounding the liquid. Then the partial pressure of the Co2 dissolved in solution within that water would be .000147psi. At 33 feet in depth of seawater the pressure exerted is 29.4 psi thus the pressure of the Co2 would be .000294psi. Decaying organic matter on the ocean floor create Co2 that Co2 in solution at a depts. of 3000 feet would represent .013524psi. and providing that water remains at that depth it will always contain that much Co2. Has no one ever noticed that a 750 Ml bottle of green wine will degas faster than a 6 gallon carboy of the same wine? Do this experiment and see for yourself. Place 750 ml of un-degassed wine in a bottle and attach an airlock. place 6 gallons of the same wine in a carboy and place them side by side. leave them for 1 month undisturbed. place a vacuum pump on the 750 and bring to 2IN-HG observe how many bubbles come from the wine. Now gently syphon 750 ml from the 6 gallons and do the same. What you will discover is the wine from the 6 gallons will produce far more bubbles, the weight of the liquid held a greater amount of Co2 in solution. the reason is the weight of the wine itself helps hold the co2 in solution. Stirring of the wine allows for an exchange of the gas. Give it a try it will be fun.
But even at that the volume of the wine was is not what I was referring to, it was the volumetric expansion of the molecules creating what I referred to in the earlier post.

 

[sour_grapes]

jody I am glad that you are using the simple answers to your simple yet very good question.

While discussion of this is good it went way over a simple answer jody needed. It certainly does not need to determine if it works because of any certain law such as Boyle's law, etc. If that discussion is wanted please open your own thread dealing with it, but in any event keep the discussion friendly and informative. Jody doesn't need to feel overwhelmed and confused.

Thank you all for understanding this and please keep any personal differences out of this.

Gosh, I would like to note that I had not seen this remark when I posted my explanation!

Roger Wilco.

 

[grapeman]

NOW THAT I HAVE YOUR ATTENTION- I HOPE- PLEASE READ THE FOLLOWING

While discussion of this is good it went way over a simple answer jody needed. It certainly does not need to determine if it works because of any certain law such as Boyle's law, etc. If that discussion is wanted please open your own thread dealing with it, but in any event keep the discussion friendly and informative. Jody doesn't need to feel overwhelmed and confused.

Thank you all for understanding this and please keep any personal differences out of this.

This is the last warning and if the discussion keeps along this path, I will divide the post into two segments. Scientific discussion is fine but if you want to do it, keep it civil and in it's own thread so new winemakers aren't intimidated.

 

[jody]

I moved the brew belt near the bottom of the carboy, about 1/4 of the way up, and I have the temp at 73F(23C). I am glad I have the temp up now. I am going to rack this weekend and do some stirring, vacuum pump, shake test, etc.

I'll let you all know how it turns out. Thanks everyone for all your help!

 

[ibglowin]

Not as long a it is topped up and under airlock. Remember 73 is room temp in the Winter months for lots of folks in the South.

 

[heatherd]

I got the brew belt on yesterday. And I only have the temp up to 66F(19C). I have the belt 1/3 of the way down the carboy(as the instructions said, but that was only for the bucket). The wine feels warmer above the belt. I am thinking as heat rises maybe I should put the belt further down the carboy?

I will take your advice and rack when I get the temp up. And drill power stir.

Thanks



By splash rack you mean keep the racking tubing at the neck and let it splash down?

I usually use the vacum pump to check if I have all the gas out, but I can see how it could be useful to remove the gas.

I will also use the shake test as you said.

Thanks!

No problem - "splash rack" means what you think, to keep the tubing at the neck and let it splash down. I also swish the tube around quite a bit to get more agitation.

You'll be able to make improvements by doing these things. Feel free to post if the splash rack and stirring do not make that impact that you're going for.

But since you stated that it's not too bad, and you and your wife don't find it terribly objectionable now, doing these things should help a bit.

After bottling, if there's still gas you can decant, and aerate to help out.

Good luck and let us all know how it goes.

Heather

 

[calvin]

Wow this thread got a little to in depth for me.

 

[richmke]

I moved the brew belt near the bottom of the carboy, about 1/4 of the way up, and I have the temp at 73F(23C). I am glad I have the temp up now.

In general, lower temps (60's) are better for white wines because the fruity essence is more volatile, and the colder temps keep them from evaporating.

For red wines, it is not as much of an issue, and the higher temps (70's) help things move along faster. That said, once you are a month or two into the process, better to have the lower temps and let time do all the work.

 

[jody]

Let us all know if raising the temp alone does the trick for you. Cheers!

I splashed racked and had quite a lot of foam. Also while drill stirring I had lots of foam and gas. I basically kept tasting the wine until I didn't have any fizz on my tongue. I also think I ended up over stirring by mistake, and introduced to much O2, Because the taste of the wine became more mellow.

Thanks all for the help I really appreciate that.

I apologize if the photos are to big.

Cheers, Jody.

 

[grapeman]

It tastes more mellow because you got the sharp C02 out. That can confuse the tongue into thinking it is higher in acid than it really is. You did good.