Jump to content


Photo

Methods For Testing For Dissolved Co2


  • Please log in to reply
3 replies to this topic

#1 Michael A

Michael A

    Look Out Ernest & Julio

  • Members
  • PipPipPipPipPip
  • 1211 posts
  • Gender:Male
  • Location:Alameda CA

Posted 28 October 2008 - 09:33 AM

To degass or not to degass; That is the question!

I have been reading a lot on the topic of de-gassing on this forum, and to sum up the consensus:

* CO2 in finished still wine is undesirable

* There are 3 popular degassing methods:

1) Agitation (stirring, shaking, etc)
Considered undesirable because it takes time and there are the dual dangers of broken glass and introduced O2

2) Vacuum degassing
Easier than agitation, but potentially harmful in that the presence of a vacuum could potentially also bleed off desirable volatiles

3) Bulk Aging
Takes time, and a wine may appear flat and still contain an undesirable quantity of dissolved CO2

I am of the personal opinion that leaving the CO2 in the wine for as long as possible is a good thing - let that slowly releasing CO2 protect my wine! Problem comes in knowing when it's all gone, and sometimes you just need to bottle and can't afford to let it sit for 2 or more years. I also don't want to subject my delicate wine to excessive agitation, nor the valuable volatiles in my wine to a vacuum if I don't have to.

So, with the hope of being able to determine the end point of degassing I started googling for effective methods for home winemakers to determine the quantity of dissolved CO2 in their wine and have come up with 3 possibilities that I was hoping the chemists amongst us (you know who you are!) would pipe in on.

Method 1: Carbodoseur
Attached File  Carbodoseur.jpg   27.46K   9 downloads
This is a ~$200 device ) that relies on physically agitating a wine sample to see how much CO2 is driven off by the process. Measuring the physical displacement, measuring the temperature, and correlating this on a graph will give a rough estimate of the amount of dissolved CO2 in a wine.
$200? It looks like a syringe that you suck the CO2 off with then measure the volume you got. Is there a way to make one of these ourselves??

Method 2: Titration
A titrimetric procedure was devised by Ernesto Gallo for the determination of CO2 in wines. This method involves fixing the sample with 50% NaOH to pH 10-11 and then titrating with a standard acid solution. The titer is recorded between pH 8.6 and 4.0, which represents the area in which CO2 is converted from the bicarbonate form to the free gas and carbonic acid. A degassed blank is titrated in the same range and its titer subtracted from the total. The difference is used to calculate the CO2 content of the sample.
Try as I might; this is the only description that I can find of this method; any way of inferring the specifics from first principals?

Method 3: Manometric pressure
The carbon dioxide in the sample is bound with 10 M sodium hydroxide. An Erlenmeyer flask
with a side arm is connected to a manometer and the carbon dioxide is released with
sulphuric acid from the prepared sample. The resultant increase in pressure is measured. It
allows quantifying carbon dioxide content.
Great instructions here


Thoughts?????
MRA
My wife always professed her desire to marry a man with a body like a Greek god. Somehow I don't think she meant one shaped like Bacchus...

#2 D&S

D&S

    What are you lookin' at?

  • Members
  • PipPipPipPipPip
  • 1123 posts
  • Gender:Male
  • Location:Pennsylvania

Posted 30 October 2008 - 06:46 AM

QUOTE (Big Boss @ Oct 28 2008, 12:05 PM) <{POST_SNAPBACK}>
To degass or not to degass; That is the question!.....

QUOTE
Thoughts?????
MRA

Years ago I made the mistake of bottling my first grape wine with dissolved CO2 in it. It was a good wine made annoying by a touch of fizziness so I understand your frustration. However, if you're trying to make non-commercial, still wines, I would not waste time and money precisely measuring dissolved CO2(g).

If you're using barrels, this is not an issue as the wine will degas in situ rather quickly. If using glass, after a few (3?) rackings over a couple of months, which are needed for clarity anyway, your wine should have lost most of its CO2(g). For young reds, I find a little racking and splashing doesn't hurt. For whites, I'm more careful, but if it tastes frizzante, gently rack again. Be patient, it pays off, and always taste before bottling.



#3 Proud Puppy

Proud Puppy

    Look Out Ernest & Julio

  • Members
  • PipPipPipPipPip
  • 1499 posts
  • Location:Manhattan, NYC

Posted 31 October 2008 - 09:07 PM

I kinda go the comnination route. To simplify my transfers I use a grntle vacuum pressure to move the wine when I rack. By the time I am ready to bottle, around 1year, there is usually nothing or very little CO2 remaining.

I tend to agree it probably helps keep the oxygen out though not significantly, but I am in no hurry to remove it unless it is delaying bottling. But that has never been a problem at 1 year. The everything complete in 4 to 6 weeks kits are a bit of a joke in my mind at least, but those you would need to degas!

Ron
Fermenting:   2014 Lanza Suisun Petite Sirah 108 Lbs;
2012 (frozen)Beckstoffer Orchard Ave Oakville Merlot 108 Lbs; 2014 Atlas Peak Cabernet Sauvignon 108 Lbs


#4 fmestas

fmestas

    Advanced Member

  • Members
  • PipPipPipPip
  • 944 posts
  • Gender:Male
  • Location:Los Ranchos de Albuquerque, NM, Elevation: 5000 ft, GDD: 3600

Posted 12 November 2008 - 05:54 PM

QUOTE (Big Boss @ Oct 28 2008, 11:05 AM) <{POST_SNAPBACK}>
To degass or not to degass; That is the question!

I have been reading a lot on the topic of de-gassing on this forum, and to sum up the consensus:

* CO2 in finished still wine is undesirable

* There are 3 popular degassing methods:

1) Agitation (stirring, shaking, etc)
Considered undesirable because it takes time and there are the dual dangers of broken glass and introduced O2

2) Vacuum degassing
Easier than agitation, but potentially harmful in that the presence of a vacuum could potentially also bleed off desirable volatiles

3) Bulk Aging
Takes time, and a wine may appear flat and still contain an undesirable quantity of dissolved CO2

I am of the personal opinion that leaving the CO2 in the wine for as long as possible is a good thing - let that slowly releasing CO2 protect my wine! Problem comes in knowing when it's all gone, and sometimes you just need to bottle and can't afford to let it sit for 2 or more years. I also don't want to subject my delicate wine to excessive agitation, nor the valuable volatiles in my wine to a vacuum if I don't have to.

So, with the hope of being able to determine the end point of degassing I started googling for effective methods for home winemakers to determine the quantity of dissolved CO2 in their wine and have come up with 3 possibilities that I was hoping the chemists amongst us (you know who you are!) would pipe in on.

Method 1: Carbodoseur
Attached File  Carbodoseur.jpg   27.46K   9 downloads
This is a ~$200 device ) that relies on physically agitating a wine sample to see how much CO2 is driven off by the process. Measuring the physical displacement, measuring the temperature, and correlating this on a graph will give a rough estimate of the amount of dissolved CO2 in a wine.
$200? It looks like a syringe that you suck the CO2 off with then measure the volume you got. Is there a way to make one of these ourselves??

Method 2: Titration
A titrimetric procedure was devised by Ernesto Gallo for the determination of CO2 in wines. This method involves fixing the sample with 50% NaOH to pH 10-11 and then titrating with a standard acid solution. The titer is recorded between pH 8.6 and 4.0, which represents the area in which CO2 is converted from the bicarbonate form to the free gas and carbonic acid. A degassed blank is titrated in the same range and its titer subtracted from the total. The difference is used to calculate the CO2 content of the sample.
Try as I might; this is the only description that I can find of this method; any way of inferring the specifics from first principals?

Method 3: Manometric pressure
The carbon dioxide in the sample is bound with 10 M sodium hydroxide. An Erlenmeyer flask
with a side arm is connected to a manometer and the carbon dioxide is released with
sulphuric acid from the prepared sample. The resultant increase in pressure is measured. It
allows quantifying carbon dioxide content.
Great instructions here


Thoughts?????
MRA


Method 4: Taste wine in question
If it tastes spritzy, fizzy or bubbly - Don't Bottle
Frank Mestas

www.elsranxos.com

"The absence of defects is not the presence of virtues" - Sean Thackrey




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users