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Oxidation reduction

I've become a more proficient taster since I've starting the hobbies of winemaking and homebrewing. Awhile back, I made a batch of Chilean Merlot from a kit. I've since decided the wine had oxidized noticeably, although it's still quite drinkable. I also tried making white wine from Jack Keller's recipe, although I added more grape juice in the middle of secondary in order to get something strong and fizzy. This tasted oxidized too, but I had a lot going on there. I wanted to make sure my taste is on, and then figure out what to do to save my butt from this happening again.

The reason I think it was oxidized is due to washing with some vinegar. The wine certainly didn't taste like vinegar, but in diluted amounts the presence was about right. The smell of the wine takes on the smell of, say, a tablespoon of vinegar in a small pot. I was washing something peculiar out of a pot using some vinegar and I caught a wiff of it. The smell was familiar and I figured out it was from the wine I made.

I have glass carboys and a manual pump for racking. I can't recall what procedure I followed when I racked from primary to secondary. Specifically, I can't remember if I let the must plop out from the top of the carboy. I know now that's a big no-no, and I had experience doing this with beer later--it had made me nervous.

I think bottling is where I'm more concerned. The procedure we followed for the wine was to fill all the bottles until the carboy was empty, and then cork. I'm trying to think of an alternative arrangement where I could lightly tap corks in as I go, preventing the bottles from being open to the wild for long.

My impression has been that the wine oxidized quicker than I would have expected, and I want to make sure that a second batch isn't so vulnerable.

Reply to
Adam Preble
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It was not from corking, I do them all at once too. I fill bottles with the siphon tube completely submerged.

Oxidation and vinegar infection are not the same thing.

Did you use citric acid to bump up the acid pre ferment? That can cause increased amounts of vinegar.

You need the presence of vinegar (usually) to get that type of infection. Don't do anything with 'live' vinegar near wine.

Were these real corks and are you sure you did not have a corky bottle rather than a vinegar problem? Corkiness is more of a musty, woody taste but it can be a horrid smell too... I really hate it when that happens. All that work for nothing.

Joe

Reply to
Joe Sallustio

I was told they were rather similar at one point. This is nice to know, since I was trying to reconcile "cardboard-like" with "vinegar-like."

This was from a kit. There were some additives but I wouldn't be able to tell you if there was citric acid. The kit's long gone anyway so I wouldn't be able to tell.

I was doing this at a friend's house, who didn't have a drop in vinegar in that place, nor for the half year he had lived there. But by "live" do you mean making vinegar?

They were real corks. I don't have an association to cork when I taste the wine. Some oak chips came with the kit to try to impart the flavor of aging in a barrel. As far as taste, I can't tell that is there.

Reply to
Adam Preble

You are a brewer right? I believe I have seen your posts on rcb.

I think you are oxidation paranoid. As long as your sulfite levels are ok, your wine will be ok.

First, get rid of the autosiphon for racking. Instead fill a racking cane with sulfite solution, and use that to start the siphon. Second, make sure your carboys are all topped up like to 1/2 an inch fromteh top. And Finally make sure you have enough sulfite. Get a test kit if yo have to.

Anyway, a vinegar smell is not oxidation. It is vinegar. That is easily formed in wine by one of the organisms that can actually survive in wine, acetobacter. It is caused by not keepig your carboys topped up and letting the bugs have too much access to air.

Reply to
Droopy

Vinegar and oxidation have nothing in common other than for a wine to turn to vinegar it must have contact with air. The vinegar requires it. That said, do not use vinegar for anything near your wine.

I think you are going to have to look elsewhere for your taste problem.

Ray

Reply to
Ray Calvert

Adam,

As others have pointed out, oxidation is different to acetification. To really experience oxidation, take some commercial wine of decent quality and leave some out in a glass overnight. The aroma should then smell oxidised (i.e., acetaldehyde, like a Sherry). This is clearly different to the smell of vinegar (e.g. ethyl acetate, like in nail polish).

As for bottling: if you are not bottling under protective atmosphere (i.e., your wine is exposed to air during bottling) then the primary source of oxygen uptake is through contact with air during *transfer*, not during the time while the wine is in bottle and waiting to be corked. Even bottling with O2 exposure shouldn't cause oxidation to the equivalent of the glass left out overnight, however. I would recommend you check you SO2 levels and ensure in future that they are sufficient, and be sure that your wine is not exposed to air significantly during storage (e.g. the bung popping out of your carboy).

HTH, Ben

Reply to
Ben Rotter

Just want to make sure you weren't confused here.

"Corky" or "Corked" doesn't refer to it tasting/smelling like a cork--it is a term for the odours and flavours that come from a bad cork--one that is infected with a bacteria that produces a chemical called TCA.

If your bottle is "corked" it will smell musty--like an old dish rag or a cardboard box that got wet sitting in your basement. I could see this being described as somewhere between cardboard and vinegar...you could not confuse this with an oak aroma or taste...

Something where between 1/10 to 1/20 of natrual corks are infected to some degree.

Reply to
CJ

Ok. You have some good leads in other posts but if it smells like vinegar I guess it is. I don't know how it got infected though. As to oxidation, another test is to check the shoulders of the wine in a slanted glass, the perimeter should be clear and you should not see any brown anywhere. Browning is an indication of oxidation.

Most store bought vinegar is dead, it was pastuerized. Live vinegar is infected with a culture of acetobacter, it can grow more vinegar.

Joe

Reply to
Joe Sallustio

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