cold stabilizing

[ibglowin]

Definitely not a gas. And the use of a vacuum will not draw it out either. It is dissolved into solution. It just hangs around looking for something to react with (like Oxygen!) A vacuum will not effect it.

Even in George's "how to video's" he has you stabilizing (adding K-Meta) first followed by degassing.

The k-meta forms S02 gases to protect the wine and what bubbles you were drawing out were likely the S02 you just added.  Degas, then add the k-meta.

 

[Wild Duk]

Well mine definetely fizzed up after adding the K-Meta. Not sure what was happeneing but it did it. Went away afterapprox. 1 minute of about 15" on the brake bleeder.....

 

[grapeman]

Mike I am not a chemist, but I was under the impression that Free S02 is a molecular gas in the wine that is not bound. That is why it reduces over time and needs to be replaced. Any free gas would seem likely to be removed with vacuum- pulled right out of the wine. When someone adds too much k-meta, what do we recommend- stir the heck out of it, why?, if it isn't a gas that can then leave the wine? When you take a whiff of a jug of high concentrate k-meta does the S02 take the wind from you?


I also refer to the article written by Scott Irwin based on Tim Vandergrift of Wine Expert



FEATURED ARTICLE - UNDERSTANDING SULFITE AND ITS IMPORTANT ROLE IN MAKING WINE



Background


Sulphur dioxide, often called sulfite or SO2, has been used in wine making for over 2000 years. It is used in modern wine making mainly for its ability to prevent fermentation of unwanted wild yeasts, bacterial action, and its anti-oxidant properties. When too much sulfite is used it will certainly affect the taste of the wine and can also cause an odor like a burnt match smell when the wine is poured into a glass. It is possible to make wine successfully without using sulfites, but this is very risky due to not having the protection against microbial contamination and oxidation. This is best left to the experts or to the very experienced home winemaker who is willing to take the risk.


There are two forms of sulfite typically used in home wine making: Potassium Metabisulfite and Sodium Metabisulfite. Potassium metabisulfite is often referred to as “K-meta” and Sodium Metabisulfite is often referred to as “Na-meta” (In the periodic table, K is the elemental symbol for potassium, while Na is the same for sodium) . Home winemakers generally prefer to use the potassium form for sulfite additions since some claim that the sodium form can cause the wine to have a `salty' flavor. Two common methods of measuring SO2 include the Ripper/titration method and the aeration oxidation method.


Uses of Sulfite


Home winemakers use metabisulfite as a sanitizing solution to rinse their equipment when making their wines. There are better cleaners available for cleaning equipment than metabisulfite but it is an excellent sanitizer. Remember, you need to clean AND sanitize. Tim Vandergrift the Technical Services Manager of Winexpert Limited recently wrote the following information on this subject: “ The sanitizing solution Winexpert recommends is at 1250 PPM, 50 grams in 4 liters, or about three tablespoons of sulfite powder per US gallon. A little heavy hurts nothing but don't go lighter. It will keep for a month or two in a sealed jug” and “ technically Sodium meta is about 8% more active in a given solution than Potassium meta. In practice, this means that if you dose with a quarter-teaspoon in 23 liters (6 US-gallons) you'll yield 20 PPM of free SO2 with Potassium and 21.6 PPM with Sodium. And both are equally effective as a surface sanitizer and wine making additive plus Sodium metabisulfite is much, much cheaper than potassium”.


How sulfite works


A portion of the total sulfite added to wine will become bound with other compounds in the wine and is therefore referred to as "bound" SO2. The remainder is called "free" SO2. "Total" SO2 is the sum of free and bound SO2. Grape and other fruit musts contain compounds that will bind with roughly 50% of the total sulfite added. While binding is not instant, it is the fastest within the first 24 hours of SO2 addition and can take 4-5 days before full bonding is complete. NOTE: when you test for sulfites you are testing the free SO2 not the total. Also when measuring sulfite levels “ppm” and “mg/l” are the same and are used interchangeably in the industry.


The free SO2 protects your must from oxidizing and browning before and during fermentation and also helps with color extraction when using fresh grapes. While sulfites will prevent fermentation of unwanted wild yeasts, today’s cultured yeasts used by home wine makers are tolerant to sulfites up to 150 ppm and higher; however, it is best to keep the free SO2 to less than 50 ppm to provide the protection you need and prevent problems with fermentation. Sulfites also protect your wine in the bottle from oxidation and spoiling from microbes. Bottled wine will slowly lose some of its free SO2 over time. That is why most instructions in wine kits tell you to add more sulfite if you plan to age your wines for an extended period of time. Since the new wine kits that come with crushed grape packs (like the Crushendo Series from Winexpert) are designed to be aged longer then come with bigger pre measure packets of K-meta.


pH and Sulfites


Molecular SO2 is the principal form of free SO2 that is responsible for anti-microbial activity. The amount of molecular free SO2 available is a direct function of the pH of your must or wine. Since the lower the pH (more acidic) the more molecular SO2 is available, sulfite additions should be calculated with reference to pH. Not every home wine maker has a pH meter so general guidelines are written so the amount of sulfite added would provide the protection your wine needs based on a average pH for the style of wine. It has been written that the amount of molecular SO2 needed to protect your wine is a level of ~0.8 mg/l. The chart below shows the amount of free SO2 needed to provide protection of molecular SO2 at the level of 0.8 mg/l. Remember that the level of free SO2 will slowly decrease over time, so if you plan to age your wine for an extended period of time you need to increase the amount of sulfite added so you don’t lose the protection over the years


Free SO2 required for a level of 0.8 mg/l molecular SO2
<TABLE border=2 cellSpacing=0 borderColor=#0033cc cellPadding=10 align=center ="tableNew"><T>
<T>
<TR ="#ffff00">
<TD width="52%" noWrap>
pH Level</TD>
<TD width="44%" noWrap>
Free SO2 </TD></TR>
<TR>
<TD width="52%">
2.8 </TD>
<TD width="44%">
8 </TD></TR>
<TR>
<TD width="52%">
2.9 </TD>
<TD width="44%">
10 </TD></TR>
<TR>
<TD width="52%">
3.0 </TD>
<TD width="44%">
12 </TD></TR>
<TR>
<TD width="52%">
3.1 </TD>
<TD width="44%">
16 </TD></TR>
<TR>
<TD width="52%">
3.2 </TD>
<TD width="44%">
20 </TD></TR>
<TR>
<TD width="52%">
3.3 </TD>
<TD width="44%">
25 </TD></TR>
<TR>
<TD width="52%">
3.4 </TD>
<TD width="44%">
31 </TD></TR>
<TR>
<TD width="52%">
3.5 </TD>
<TD width="44%">
39 </TD></TR>
<TR>
<TD width="52%">
3.6 </TD>
<TD width="44%">
49 </TD></TR>
<TR>
<TD width="52%">
3.7 </TD>
<TD width="44%">
62 </TD></TR>
<TR>
<TD width="52%">
3.8 </TD>
<TD width="44%">
78 </TD></TR>
<TR>
<TD width="52%">
3.9 </TD>
<TD width="44%">
98 </TD></TR>
<TR>
<TD width="52%">
4.0 </TD>
<TD width="44%">
124 </TD></TR></T></T></TABLE>


Forms and Measurement


There are basically two forms of sulfites which are powder form and campden tablets. Home winemakers due to the ease of adding tablets without measuring as with the powered form often use campden tablets. Campden tablets were designed to have a mass of 0.44 grams of potassium or sodium metabisulfite. Consistency of the tablet size in manufacturing is questionable, and many winemakers claim there is little certainty that tablets contain the amount of metabisulfite they are intended to. I ran my own series of tests on two different brands of campden tablets and found up to a 60% variation in the amount of free SO2 that was added. Some winemakers claim that the fillers used in making campden tablets to increase the bulk size of the tablet taint wine flavor and affect clarity. They also need to be crushed and completely dissolved in order to work properly. Using the powdered form requires an accurate measurement with a good set of measuring spoons (1/8,1/4,3/8 tsp). Better yet I prefer to use a good quality gram scale to measure the proper amount as it is done with the measured packets included in wine kits.


Summary


As you can see sulfites play an important role in sanitizing equipment, preparing musts, and protecting your wine after fermentation and bottling. If you are making your wine only from kits you should follow the instructions included in the kit for additional sulfite additions for extended aging. Making wine from fresh grapes or fruit requires more knowledge of adjusting acid levels and pH and a decision of what type of sulfite to use plus a good way to measure it. I hope this information will help you understand the use of sulfite in wine making and why it is an important part of producing a quality wine that you can be proud to say you made yourself!


Scott Irwin


References:


Ben Rotter, tripod.com


Tim Vandergrift, winepress.com

 

[Wade E]

There are 2 types of S02 which Im sure both of you know, there is bound and free S02. The reason that you had bubbles after adding the k-meta is any C02 in the wine will be attracted to any foreign object and that object at this time is k-meta and when it attaches to it it is able to break its bond and release itself. Its kind of like when you add oak cubes to a wine and you get a volcano so in short adding k-meta will usually cause the volcano or at least give you some action.
K-meta is a gas and also gets dissolved into wine which will bond and not come out. When we sanitize with k-meta its not the liquid contact that is mainly doing the sanitizing, its the gases being released. Using tap water and distilled water will create differnt release times also. A member f my forum actually taught me this a fw weeks ago. If you use tap water the k-meta can take sometimes a day or 2 to really start creating gases or the smell that knocks us on our butt, Try using distilled water and is almost immediate. Adding citric acid to this mixture brings it out even faster and makes the sanitizing slotion even stronger but will also reduce the amount of time that your solution will last due to the citric acod making the S02 come out of solution sooner.

 

[ibglowin]

You guys are going to make me use my brain which I hate to do!

SO2 is a gas but it's a gas that is soluble in aqueous solutions including wine meaning it has "dissolved" into the wine forming a homogeneous solution.

Free SO2 just means it is available to react with something or undergo reduction. Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion. Once it has undergone reduction, it is bound (tied up). And is no longer able to help protect the wine anymore.

So when we say that our (free) sulfite levels have dropped, its not because the SO2 has just evaporated into thin air, its because it has reacted with something and is now bound and no longer available to protect the wine. The amount of sulfite stays the same, its just the ratio of free to bound keeps sliding as the free sulfite reacts and thus gets "used up".

Once the sulfite is dissolved into solution pulling a vacuum on your wine will not suck out all your sulfites.

Here is a quote straight from George's degassing article.

"There are also some questions about vacuum degassing. Will the vacuum remove alcohol, sulfur dioxide or the esters contributing to the aroma and taste? According to Tim Vandergrift, technical services manager for WinExpert, you cannot extract a measurable amount of alcohol or significantly change sulfite levels with a vacuum apparatus and even high levels of vacuum (&gt;24 inches mercury) don’t damage ester levels."

Mike I am not a chemist, but I was under the impression that Free S02 is a molecular gas in the wine that is not bound. That is why it reduces over time and needs to be replaced. Any free gas would seem likely to be removed with vacuum- pulled right out of the wine.

 

[robie]

Wade,
Are you saying some free SO2 will bind to the CO2, thus be pulled out by the vacuum, along with that CO2?

Ugh! I'm getting a headache thinking about all that gas.

 

[grapeman]

I guess you must be right about this Mike. I guess I incorrectly assumed that since we smell sulfur, there must be volatile sulfur present. Since there was volatile sulfur, it would be subject to sucking it out before it goes into solution. Did I think all the S02 would be instantly sucked out? No. But if I add 25 milligrams of sulfur as free S02 I don't want to pull it out- even a fraction of it. I want to give it time to work it's way into the wine where it can do it's thing.


Thanks for pointing that out. I gave all of us a chance to learn more about this protectant.

 

[ibglowin]

K-meta is a gas

Technically K-Meta is a salt crystal. When we add it to water or our wine it dissociates or breaks down into potassium oxide and sulfur dioxide ions via this reaction:

K2S2O5(s) → K2O(s) + 2SO2(g) (one component is still a solid, the other is a gas)

Both components fully dissolve into solution.

When we add a top up 1/4 tsp to 6 gallons of wine we are adding approx 75 ppm of free sulfites.

When you make up your sanitizing solution your are making up aprox a 10,000 ppm solution of free sulfites which is why you almost fall over if you get a wiff of your sanitizing solution.

 

[ibglowin]

I guess I incorrectly assumed that since we smell sulfur, there must be volatile sulfur present.

There is some volatile SO2 floating around for sure and thats what we smell but its only trace amounts in comparison to what's been dissolved into solution.

Our noses are incredibly sensitive.

Some people can detect cork taint or 2,4,6-trichloroanisole (TCA) down to the 4-6 ppm range.

 

[Wade E]

When you make a S02 solution isnt it the gases that do the sanitizing hence the corkidor? This is also what is shipped in our bags of corks.

 

[ibglowin]

You saying you have corks shipped in sulfite?

The 10,000ppm (1%) sanitizing solution will have plenty of volatile SO2 that will kill bugs with the vapor fumes. Not so much in the 75ppm top up solution that gets added to your carboy.

 

[Wade E]

Georges corks are shipped in bags with a S02 gas in them. Do not open a bag and take a wiff!!!!!!!!! Like the sulfite solution you use to sanitize all your equipment, its not the solution doing most of the work, its the gases do so. Thats another thing when sanitizing corks, you pour the solution over the corks which should be in a collander over a bucket and after doing so put a lid over both of these and let the gases come up and do the work. Also when sulfiting your win e in the beginning to stall the wild yeasts, this is why we wait for 24 hours for the excess sulfite to disperse out so that we can safely add our ptreferred win e yeast and if over sulfited why we stir the snot out of it to dissipate out the excess.

 

[ibglowin]

I have 2 bags of 100 Perfect Agglomerate (#9 x 1.75) corks from George.

Just opened both and took a big whiff.

Zero sulfite.......

 

[Wade E]

Mine almost knocked me over!

 

[ibglowin]

Are you using the exact same type of cork from George? Are you ordering in larger quantities than 100? Mine are in a zip lock bag with a label on them. Perhaps larger bags are sealed from the factory?

Just throwing out possible differences including I have a HIGH tolerance to Sulfites these days!