White wine seems carbonated

[crafty2148]

I am new and I apologize if this has already been talked about. I have searched the forums and can't find one that matches up exactly with what my issue is.

I have been making wine for about 8 years now from wine juice shipped from Tuscany. One of the wines i make is a Pinot Grigio. I go through the normal fermentation process (i stir vigorously everytime i do a hydrometer reading each day). I then bulk age my wine in my basement where it stays around 64 degrees. With Pinot Grigio i usually age it for about 2-3 months to get the perfect taste and allow it to fully degas and clear. I have had zero issues with this timeframe in the past.

This time for some reason, my wine appears to be carbonated. When i put the siphon into the carboy to transfer, the siphon is immediately covered in bubbles and a group of bubbles rise to the top. I then filled one bottle, put my hand over the opening and tipped it upside down and then back upright. It bubbled like a champagne. The taste is perfect but has a small "bite" to it.

I have not had this issue before and changed nothing about my process. Am i correct in thinking that this wine still has a decent amount of CO2 in it? I did another Hydrometer reading to make sure it wasn't going into another fermentation but the reading was below 1.00 BRIX and less than 0%.

If it is CO2, is there something else i need to do to release this gas?

 

[NorCal]

Yes, CO2. There are degassing techniques you can do, or simply give it time. Once you bottle it, the CO2 is there to stay, so make sure you are happy with the taste profile before you put the cork in.

I have Chardonnay that is 6 months old and still needs some more time. The retention of the gas is a function of a few things, but how much CO2 that was produced during fermentation and the temperature the wine was stored in after fermentation are the bigger ones.

 

[QuiQuog]

Temperature was the first thing that came to my mind. I've run into that before also. I would get it into a warmer part of the house for a while. I've heard good things about vacuum racking because it doesn't expose it to much oxygen. If you could get it warmed up and also vacuum rack that might work. Or warm it up and try one of the various purpose built drill attachments, like a 3 pronged degassing whip. Or warm it up and splash rack. Basically, warm it up.

 

[Hazelemere]

I am new and I apologize if this has already been talked about. I have searched the forums and can't find one that matches up exactly with what my issue is.

I have been making wine for about 8 years now from wine juice shipped from Tuscany. One of the wines i make is a Pinot Grigio. I go through the normal fermentation process (i stir vigorously everytime i do a hydrometer reading each day). I then bulk age my wine in my basement where it stays around 64 degrees. With Pinot Grigio i usually age it for about 2-3 months to get the perfect taste and allow it to fully degas and clear. I have had zero issues with this timeframe in the past.

This time for some reason, my wine appears to be carbonated. When i put the siphon into the carboy to transfer, the siphon is immediately covered in bubbles and a group of bubbles rise to the top. I then filled one bottle, put my hand over the opening and tipped it upside down and then back upright. It bubbled like a champagne. The taste is perfect but has a small "bite" to it.

I have not had this issue before and changed nothing about my process. Am i correct in thinking that this wine still has a decent amount of CO2 in it? I did another Hydrometer reading to make sure it wasn't going into another fermentation but the reading was below 1.00 BRIX and less than 0%.

If it is CO2, is there something else i need to do to release this gas?

leave it alone. Just keep it cool so it doesn't ferment down to SG 0.992 during storage. A fridge is perfect.

 

[crafty2148]

leave it alone. Just keep it cool so it doesn't ferment down to SG 0.992 during storage. A fridge is perfect.

So do you think it just needs to keep degassing itself through time?

 

[winemaker81]

You could try stirring it for 1 minutes, changing directions half way through. No need to "whip it" as some degassing instructions claim. Just get the wine moving -- if there is excess CO2, some will be expelled.

Most wines degas relatively quickly (within 4 months) but some are stubborn.

 

[crafty2148]

You could try stirring it for 1 minutes, changing directions half way through. No need to "whip it" as some degassing instructions claim. Just get the wine moving -- if there is excess CO2, some will be expelled.

Most wines degas relatively quickly (within 4 months) but some are stubborn.

Yeah it's very odd that i haven't had an issue in the past 8 years but now all of a sudden it won't degas.

 

[winemaker81]

Yeah it's very odd that i haven't had an issue in the past 8 years but now all of a sudden it won't degas.

Every batch is different. You may have 99 batches follow the same process flow ... but #100 diverges.

Keep in mind that wine is the result of numerous biological and chemical processes, and once the wine is wine, the progression of processes does not stop. There are dozens of variables, many of which we cannot influence, and physics plays a role in the processes.

When I think about it, I find it more amazing that most wines follow a common process flow.

 

[Rice_Guy]

2 So do you think it just needs to keep degassing itself through time?

maybe if heat is added in summer, ,,,
* the solubility of a gas is proportional to the partial pressure (of that gas) in the head space above the liquid.
* CO2 is more soluble in a cold solution.
* time or mechanical mixing is required for degassing, if you only put energy into the carboy it still could take a month.
* if you don’t put energy in,, as heat or reduced pressure you will not degas, ,, ever

OK, as noted already you can warm up the wine/ add heat energy. Practically speaking if you have gone through summer it should have been exposed to warmth and be good enough for spring and winter gas solubility conditions. An easy answer would be to slip a heating pad under the carboy/ band heater around it for a week. Yes natural degassing takes time but in a factory setting pumping (severe mixing) let’s one degas instantly.

You could decrease the percentage of CO2 in the ullage as by flushing with nitrogen and in a factory where we have that we might sparge gas into the tank, Yyou could pull a vacuum on the carboy which again decreases the pressure of CO2 in the head space. , ,,, This is the direction I encourage if you have access to a vacuum source and a check valve. My test set up might have a VacuVin rubber cork connected to a universal stopper with two inches of 5/16” tubing, ,, and pump out the head space with the VacuVin pump several times a day for a week. OR take a small motorized vacuum with another universal cork on top of the VacuVin for half an hour.

As a wine judge I tend to ignore a few bubbles on a glass. I don’t think it kills the flavor, ,, it may improve the freshness sensation. BUT gushers should be avoided.

 

[crafty2148]

maybe if heat is added in summer, ,,,
* the solubility of a gas is proportional to the partial pressure (of that gas) in the head space above the liquid.
* CO2 is more soluble in a cold solution.
* time or mechanical mixing is required for degassing, if you only put energy into the carboy it still could take a month.
* if you don’t put energy in,, as heat or reduced pressure you will not degas, ,, ever

OK, as noted already you can warm up the wine/ add heat energy. Practically speaking if you have gone through summer it should have been exposed to warmth and be good enough for spring and winter gas solubility conditions. An easy answer would be to slip a heating pad under the carboy/ band heater around it for a week. Yes natural degassing takes time but in a factory setting pumping (severe mixing) let’s one degas instantly.

You could decrease the percentage of CO2 in the ullage as by flushing with nitrogen and in a factory where we have that we might sparge gas into the tank, Yyou could pull a vacuum on the carboy which again decreases the pressure of CO2 in the head space. , ,,, This is the direction I encourage if you have access to a vacuum source and a check valve. My test set up might have a VacuVin rubber cork connected to a universal stopper with two inches of 5/16” tubing, ,, and pump out the head space with the VacuVin pump several times a day for a week. OR take a small motorized vacuum with another universal cork on top of the VacuVin for half an hour.

As a wine judge I tend to ignore a few bubbles on a glass. I don’t think it kills the flavor, ,, it may improve the freshness sensation. BUT gushers should be avoided.

I am like you, a little carbonation does not bother me. I am more worried about popped corks during storage. Currently my carboy is in my basement where it maintains 64 degrees. Do you think just moving it upstairs where the temperature is around 70 would help accelerate the degassing? If so, do you think the warmer temperatures would hurt the taste of the wine?

 

[Rice_Guy]

* moving the wine to 70 will not significantly hurt the wine. With warehouse storage the shelf life is measured in years. You should not taste a difference.
* Natural cork has the ability to breathe. I wouldn’t expect the cork to pop out due to increased pressure. How much ullage do you put on a bottle? Wine/ liquids will expand as they warm. As an example if I pasteurize a cider with 1/2 to 3/4 inch of ullage at 140F it will expand enough to push a cork out. (Never pasteurize bottles with corks). Ordinary Bottles are rated at somewhere around 1.25 atmosphere of pressure (3.25 psig above atmospheric). The first risk I see is bottle bombs, not blowing a cork. Most of the bottles I recycle look thicker and probably do 2 atmospheres, I haven’t heard stories of the cork popping in a hot warehouse.
* one goal is to have the finished wine look good when it is served. If you are serving at 84F in summer the gas law would say that the wine is in equilibrium / will not foam if it spends some time at worst case conditions. ie it may have some bubbles in the goblet if you process at 70F and serve at 84.
Time? With a vacuum system I have seen that in half an hour the foaming stops and the pump just spins, ,, by the next morning it will have re-established a soluble gas equilibrium and usually will foam for five minutes. After this it is done.

 

[crafty2148]

* moving the wine to 70 will not significantly hurt the wine. With warehouse storage the shelf life is measured in years. You should not taste a difference.
* Natural cork has the ability to breathe. I wouldn’t expect the cork to pop out due to increased pressure. How much ullage do you put on a bottle? Wine/ liquids will expand as they warm. As an example if I pasteurize a cider with 1/2 to 3/4 inch of ullage at 140F it will expand enough to push a cork out. (Never pasteurize bottles with corks). Ordinary Bottles are rated at somewhere around 1.25 atmosphere of pressure (3.25 psig above atmospheric). The first risk I see is bottle bombs, not blowing a cork. Most of the bottles I recycle look thicker and probably do 2 atmospheres, I haven’t heard stories of the cork popping in a hot warehouse.
* one goal is to have the finished wine look good when it is served. If you are serving at 84F in summer the gas law would say that the wine is in equilibrium / will not foam if it spends some time at worst case conditions. ie it may have some bubbles in the goblet if you process at 70F and serve at 84.
Time? With a vacuum system I have seen that in half an hour the foaming stops and the pump just spins, ,, by the next morning it will have re-established a soluble gas equilibrium and usually will foam for five minutes. After this it is done.

There is usually about 1 inch of open space (or slightly more) between bottom of cork and wine.