Need help with oxidation

[PharmerMike]

Looking for some assistance with what I believe is oxidation in my wines made from juice buckets.

I have landed on juice buckets as the sweet spot for me after making several wines from concentrates, Dragon's Blood, several country wines and one kit. I have enjoyed these wines from juice as much or more than many $25.00 bottles I have purchased. In fact, my tasting notes at bottling typically contain words like "superb". I actually enjoy them young, but also want to enjoy them over several years.

Here's my issue: I notice a gradual deterioration in flavor over time, with a few becoming undrinkable. I believe this to be oxidation. I would describe the taste as mostly bitter. I've read that wine suffering from oxidation can taste metallic, but I have not noted that. I do notice a more brown color and cloudiness in the oldest bottles.

Looking back through my notes, I have used K-Meta in each batch (1/4 tsp per five gallons), typically with each racking. I tend to watch the carboys and don't believe I have ever had one where the airlock went dry. My typical time frame from inoculating with yeast to bottling has been 5-6 months. My normal process is to chapitalize to an SG of 1.100 and ferment to dry. I use RC-212 as my go-to yeast for reds. I have used the natural, aggregate corks in my 750ml bottles and all bottles are stored in a basement horizontally. I'm sure the temperature varies some from winter to summer, probably from high 50's-low 60's in winter to high 60's-low 70's in summer.

I currently have the following batches in storage:

Zinfandel- Fall 2016: Undrinkable

Chilean Cabernet and Carmenere- Spring 2017: Beginning to note oxidation in some of the bottles

Sangiovese- Fall 2017: No noticeable taste difference

Syrah and Malbec- Spring 2019: No noticeable taste difference

Based on the fact that it doesn't seem that my Zinfandel was a one-off issue, I have made the following changes:

1. Using synthetic corks for all wine.
2. Adding a K-Meta wash of all wine bottles after the initial sanitation before filling and corking.

My goal is to keep some from each batch and enjoy them years later. Currently, I feel compelled to drink my oldest wine first before signs of oxidation appear.

Grateful for any suggestions you have to address this issue. I have 18 more gallons of Chilean juice on the way and would like to learn from my mistakes.

 

[salcoco]

the only thought I have is check the viability of the k-meta if more than 1 year old change it out to something new.

 

[winemaker81]

How much head space did you have in the carboys during bulk aging? I didn't spot any red flags in your description, and while your storage conditions are not ideal, they are the ~same as mine and I've aged wines 10 years.

One possibility is the older wines are simply aging out. Reds made from fresh grape have aging potential due to constituents such as tannin leached from the skins and flesh during fermentation. Juice bucket reds do not have that, so the aging potential is probably much reduced. I can't say for sure, but juice bucket reds may have the same lifespan as whites, which is often 3 to 5 years (or less).

Check each Zin bottle, if undrinkable, dump it. If palatable, use it soonest. Same with the Cabernet and Carmenere. I wish I had a better answer.

Watch the newer batches. I'd start using them up once the older batches are gone.

For future reference, buy grape skin packs to add to the wines during fermentation. This should extend longevity and produce a more robust wine.

 

[PharmerMike]

the only thought I have is check the viability of the k-meta if more than 1 year old change it out to something new.

Thank you. That is very helpful. I wasn't aware that could be an issue, since I didn't see an expiration date on the package. I have ordered fresh K-Meta, and will write the date on the package when I open it so it gets discarded after 12 months.

 

[PharmerMike]

How much head space did you have in the carboys during bulk aging? I didn't spot any red flags in your description, and while your storage conditions are not ideal, they are the ~same as mine and I've aged wines 10 years.

One possibility is the older wines are simply aging out. Reds made from fresh grape have aging potential due to constituents such as tannin leached from the skins and flesh during fermentation. Juice bucket reds do not have that, so the aging potential is probably much reduced. I can't say for sure, but juice bucket reds may have the same lifespan as whites, which is often 3 to 5 years (or less).

Check each Zin bottle, if undrinkable, dump it. If palatable, use it soonest. Same with the Cabernet and Carmenere. I wish I had a better answer.

Watch the newer batches. I'd start using them up once the older batches are gone.

For future reference, buy grape skin packs to add to the wines during fermentation. This should extend longevity and produce a more robust wine.

Thank you.

I top off my carboys in secondary fermentation to make sure the top of the wine is in the narrowest part of the carboy, typically within an inch of the bottom of the stopper for the airlock. I have used a few tablespoons of wine tannin powder in the juice when fermentation begins, but your comment seems to suggest that there are other components in the grape skins that would help prevent oxidation.

I'm beginning to believe that if I'm committed to using juice buckets, I should only make what I can reasonably drink or gift within three years. If others have had a different experience, I would appreciate your thoughts.

I'm learning a lot. Thanks for the responses.

 

[winemaker81]

It sounds like you're doing the correct things. My comment regarding longevity is an educated guess, based upon knowledge of the differences between red and white wines, fermentation in general, and the fact that it appears all bottles of Zinfandel appeared to fail in a short timespan after nearly 5 years. This indicates a systemic problem, IMO related to the fruit. While it could be corks or storage conditions, that (again IMO) seems less likely.

One year I purchased really crappy Cabernet Sauvignon against my better sense, and all bottles went bad in a short time frame about a year later. Years prior to that I had good quality whites that I kept too long, and they also started to go bad in a short time frame.

I could not quickly locate a reference that states the constituents extracted during red grape fermentation, but it's more than tannin.

Keep in mind that your newer wines will not necessarily go bad in the same time frame. It's possible you could get more lifespan, but there's no way to tell without waiting, which has risks.

I'm of two minds regarding your comment about using the wine within 3 years. Given that the reds don't have the oomph of skin fermented reds, it also means they age faster and are drinkable sooner, so using up the wine in 3 or 4 years is getting you the wine's best. Since you're really happy with the quality, stick with the plan of using the wine up and planning an end-of-life in the 3 or 4 year range.

OTOH, adding a grape skin pack during fermentation should give you more longevity. Get a nylon bag for winemaking and put the skins in it to simplify removal. You can press the skins in the bag.

Or do both. I suggest making a batch with skins. Use that as a comparison tool -- does it age slower? do you like it more or less than the non-skin wines? You may decide to do both, so you have some wines that will age longer, and some not. Best of both worlds.

 

[PharmerMike]

It sounds like you're doing the correct things. My comment regarding longevity is an educated guess, based upon knowledge of the differences between red and white wines, fermentation in general, and the fact that it appears all bottles of Zinfandel appeared to fail in a short timespan after nearly 5 years. This indicates a systemic problem, IMO related to the fruit. While it could be corks or storage conditions, that (again IMO) seems less likely.

One year I purchased really crappy Cabernet Sauvignon against my better sense, and all bottles went bad in a short time frame about a year later. Years prior to that I had good quality whites that I kept too long, and they also started to go bad in a short time frame.

I could not quickly locate a reference that states the constituents extracted during red grape fermentation, but it's more than tannin.

Keep in mind that your newer wines will not necessarily go bad in the same time frame. It's possible you could get more lifespan, but there's no way to tell without waiting, which has risks.

I'm of two minds regarding your comment about using the wine within 3 years. Given that the reds don't have the oomph of skin fermented reds, it also means they age faster and are drinkable sooner, so using up the wine in 3 or 4 years is getting you the wine's best. Since you're really happy with the quality, stick with the plan of using the wine up and planning an end-of-life in the 3 or 4 year range.

OTOH, adding a grape skin pack during fermentation should give you more longevity. Get a nylon bag for winemaking and put the skins in it to simplify removal. You can press the skins in the bag.

Or do both. I suggest making a batch with skins. Use that as a comparison tool -- does it age slower? do you like it more or less than the non-skin wines? You may decide to do both, so you have some wines that will age longer, and some not. Best of both worlds.

@winemaker81 - very helpful comments in both posts. I appreciate it!

 

[Ajmassa]

you’ve definitely got something goin on. those wines should not be goin bad on ya this soon. Before i really immersed myself into winemaking i was doing a bucket or 2 a season. no frills. no nutrients. no so2 at all. no mlf. no nothing. just fermented dry. racked a couple times. bottled at 6-9mos. always drank within 1.5yrs.

had a cab sauv bucket made this way. was just ok. nothing special. found a discarded bottle over 4 years later. was the best damn wine i’d ever made at that point. was delicious. and remember this was zero sulphites and less than ideal storage.

and your doing all the precautions. they shouldn’t be going south like that. somethings up.
and your description (bitter & browning) def sounds like it’s oxidizing for some unknown reason.

 

[Rice_Guy]

* from the posts I am assuming you don’t test for free SO2. The quality of my fruit wines improved the year I assumed zero free SO2 and added the max each racking. I have a vinters club project of testing a grape wine every month to see what happens, ,, but haven’t gotten ready to use chemicals yet.
* I vacuum cork with Nomacorc to reduce bottle shock/ increase shelf life.
* red grape contains natural antioxidants and survives better, looking at club buckets over several years 10 ppm free SO2 is typical. White juice will typically come with 0 SO2 or a trace (one drop pushes it off scale).
* I have seen organic red wine WO added meta and it was OK. The same winery had oxidation on all their fruit wines.
* I posted a set of company webinars on oxidation/ reduction. As a home wine maker I don’t think it is possible to get excellent shelf life, our batch size (risk of air per gallon) is too small. For most wineries the greatest oxidation risk is in the 750 ml bottle. ,bulk storage contains risk primarily at racking. ———
This webinar starts with an overview of wine degradation over years of storage and finishes with a review of bottle closures with oxygen transmission data. Of note; at the seven minute point it mentions an article that influenced Australian wineries to favor low oxygen transmission closures. The impact of air in early processes such as long pressing increases dissolved oxygen which increases measured degradation, however one don’t see this till it is bottled, 2) metals are required to catalyze/ speed up wine reactions, 3) data shows the wine chemistry (redox potential) is more important than the type of bottle closure, 4) total oxygen at packaging is more important to shelf life than the closure type. All wines consume oxygen (can become reductive) but how fast?, new closures might scavenge sulfur (reductive) aromas, 43 minutes
www.youtube.com/watch?v=09vejFiudrM * Closures – latest understanding of their impact, Presenter - Dr Eric Wilkes (The_AWRI) 2017 Over the last few decades the range of closures that have become available to the wine industry has increased significantly, along with the claims and counter-claims about their benefits for the storage and maturation of wine. The Australian Wine Research Institute has now conducted numerous closure trials in red, white and even sparkling wines. This webinar will present the current understanding of the impact that closure selection can have on wine development, including the role of oxygen, transition metals and volatile sulfur compound development, and the underlying drivers behind the chemical changes that occur as a wine ages.

by the way welcome to wine making talk

 

[Steve Wargo]

I rack wine twice after secondary fermentation (keep in 5-6gal carboys). After a year or so wine is racked one more time, add SO2 and bottle (oak and TA adjustment already complete before bottling). Maybe check your TA(acid) levels and tannin for taste. If there is too little of one or both that might point to reasons why the wine is turning early on you. Also why you can drink it early. One has to wonder the reason why there are 100 yo bottles of French Pinot Noir Red that taste bright after opening, besides the perfect year-round storage/temp conditions in the caves. In Eastern Europe, there are some homemade wines that you can't even approach for at least 5 years. Usually, those in East Europe are stem on fermentations and very harsh wines that need to mellow. You can try heavy oak sometime after 2ndary fermentation and raise the TA level beyond normal for the wine that you want to age + 3-years. Use smaller 3-gal carboys to experiment. Half early drinker(3 yrs or less), the other half long age heavy oak+TA (5yrs + drinkers). Or leave your process the same and drink the oldest more often. JMO. Good luck.

 

[PharmerMike]

Thanks to @Steve Wargo, @Rice_Guy , @salcoco , @Ajmassa , @winemaker81 for your helpful responses!

Doing some research and work next on measuring TA and free SO2 to see if I can get a better outcome going forward.