K-Meta and oxygen control

[sremick]

So I have 4 carboys bulk aging at the moment. The oldest is from last April.

My understanding about the general rule of adding 1/4 tsp K-meta every 3 months is to control oxygen/oxidation. Presumably because people are re-racking every 3 months to potentially introduce new oxygen into things?

If I'm using argon and a vacuum on my carboys, therefore do I not need to stress out about constantly putting K-meta in?

 

[Rice_Guy]

people are re-racking. . If I'm using argon and a vacuum on my carboys, therefore do I not need to stress out about constantly putting K-meta in?

The rule is you want 25 or 30 ppm of SO2 in your wine, for those of us who do not own a Vinmetrica or use Titrets we simplify by saying when you rack (usually 3 months) add metabisulphite.
? what is your SO2 ?
You shouldn’t hurt things by following the rule as well as using argon. Another way to state the rule is don’t put enough in so that you smell it and keep below 300 ppm total added metabisulphite. * If you can smell sulfur don’t make the addition. * If you measure 25 ppm don’t add. * Reds have built in antioxidants and might be OK however whites and fruit wines seem to eat SO2 so I would add metabisulphite , , or used a measured calculation.

 

[sremick]

The rule is you want 25 or 30 ppm of SO2 in your wine, for those of us who do not own a Vinmetrica or use Titrets we simplify by saying when you rack (usually 3 months) add metabisulphite.

I guess I was trying to get a sense as to whether you still need to add some K-meta every 3 months even if you aren't racking and you're using a gas blanket to shield from O2.

? what is your SO2 ?

Not sure quite yet, as I haven't been testing super frequently due to costs of materials per test. I need to find a local source for 25% phosphoric acid.

Reds have built in antioxidants and might be OK however whites and fruit wines seem to eat SO2 so I would add metabisulphite , , or used a measured calculation.

Well I'm only making red (and cranberry, eventually raspberry and some day maybe cherry).

 

[mainshipfred]

When I first sulfite after the completion of MLF I always sulfite to 60-65 ppm. My thought is it's going to sit there for 8+ months. I will do a racking after 3 months and check the levels but more than likely won't rack again until the 8 month period. The barrels I do check a little more often.

 

[Johnd]

The ultimate goal of sulfite management is to keep an appropriate amount of sulfite in your wine for your wine's color and pH. The 1/4 tsp / 6 gallon carboy per 3 months is a simplified "rule of thumb" for those who don't have the ability to test their wines sulfite. Except with high pH wines, I've always found it to be a little heavy handed.

The purpose of sulfite management is two-fold, as sulfite protects your wine from oxidation, and it also protects it from unwanted microbial action. Managing your headspace with inert gas will certainly protect your wine from oxygen exposure and subsequently from oxidation. Much of the microbial action we desire to combat is also a result of oxygen exposure, many of these bugs need oxygen to their dirty deeds, so inert gas will help in this arena as well.

I can't say that I know that if you have zero oxygen in your headspace that you are safe from all microbial action, because I don't know if that is the case or not.

To answer your question, personally, I don't think you need to stress out about sulfite management given your current practices with headspace management, but I wouldn't totally ignore sulfite management. In my wine environment, without headspace purging with carboys being stored and not racked, sulfite levels have remained acceptable for much longer than 3 months at a clip. Though it's nearly impossible to have zero oxygen in your headspace, if you have a good seal on your carboys, and pay a little attention to sulfite, you're probably way ahead of the game.

 

[Ajmassa]

I’ve noticed that a full 1/4 tsp is always more than what’s actually called for, and the levels don’t drop significantly in 3 months even with a racking—usually*. So the rule of thumb is basically- ‘better safe than sorry’

But even though you aren’t testing ppm and using Argon you can still make logical so2 decisions— and it’s all about that PH!!!!
I’ve noticed my lower ph wines, already requiring a lower so2 level, hold their levels much better over time compared to high ph wines.
So when testing is a hassle (which it can be) and contemplating - “do I or don’t I?” - I’ll lean towards giving the high ph wines a dose and more comfortable letting the lower ph wines go for a while.

 

[mainshipfred]

For those of you that get Winemaker Magazine there is a good article on the topic in the current edition. I haven't read the whole thing but one thing they discuss is managing the levels of dissolved oxygen. The other interesting topic was the volume of wine being made and dealing with surface to air ratios similar to oaking in small barrels. I more often then I would like to I admit have to dump 1/2 to 1 gallon carboys of wine when the same wine in 25 to 30 liter barrels and carboys are unaffected by the spoilage.

 

[Ajmassa]

For those of you that get Winemaker Magazine there is a good article on the topic in the current edition. I haven't read the whole thing but one thing they discuss is managing the levels of dissolved oxygen. The other interesting topic was the volume of wine being made and dealing with surface to air ratios similar to oaking in small barrels. I more often then I would like to I admit have to dump 1/2 to 1 gallon carboys of wine when the same wine in 25 to 30 liter barrels and carboys are unaffected by the spoilage.

Eh. I chalk that up to collateral damage. When dosing so2 I disregard all the ‘extras’ bottles also.
But it also works in our favor too. I remember having a 5gal & 1gal of the same wine aged about a year, never combining. The 1gal was delicious and noticeably more mature than the carboy— giving a blueprint for how the wine would mature I assumed.
But managing the DO levels is way beyond my threshold of the technical/labwork part of the hobby I’m willing to do. I’m already to deep! But I do need to renew my WMM subscription now that I’ve been reminded.

 

[mainshipfred]

I have the ability but don't measure it very often. Lately I've just run argon through a sparging stone for a few minutes prior to bottling.