Chemistry/flavor of bottle aging vs. multi-hour decanting?

In a follow up to my question in the thread "Tastiest within two years," I wonder if some could help me understand what is going on in long bottle aging versus, say, a 5 hour decanting.

Clearly, oxidation is an important part of both processes, one of which goes much faster, presumably because of the greater oxygen exposure. For the 5 hour oxidation vs. the 5 year oxidation, what are the flavor differences?

Also, what other non-oxygen based aging is occurring during the long cellar aging that does not occur in the 5 hour decanting? What are the types of flavor/aroma changes associated with these types of non-oxygen based chemical changes?

Thanks and Happy Thanksgiving,

Greg

No chemist I, but I do know that during aging, polyphenols (mostly tannins) polymerize into longer and heavier chains and parcipitate out of solution forming sediment.
Also alcohols and acids form esters which in turn are broken down by water to alcohols and acids which then interact producing yet more esters, and so on.
Hence, aged wine is softer (less tannin and that which remains is in longer chains), lighter in color (the color compounds are also involved in tannin polymerization), and the wine becomes more complex (as the number of esters and chemical compounds multiply and change or time).

And to answer the hidden question in all this; decanting does not take the place of aging - all it does is add oxygen to the wine.

Best, Jim

I agree with Jim decanting does not take the place of aging. Scientist do have some understanding of what takes place in a bottle of wine as it gracefully ages, but as far as understanding why or the “role” the enclosure has in all of this they know little. Some will tell you the only function of the enclosure is to seal it properly so that it could reach the consumer the way the winemaker intended. But just as Jim stated, in age worthy wines-primary fruit aromas and flavors, secondary fruit aromas and flavors, and bulk aging fruit aromas and flavors intermarry and become bottle aromas and flavors. Does the type of enclosure play a role this?

Happy Thanksgiving!

Salute

Multi-hour decanting provides rapid oxidation.

The very long-term chemical processes involving tannin chain elongation and many other things, will not take place during a multi-hour decantation.

There are some chemical processes that take months to years to complete that cannot be duplicated in under a day. Not all of these are oxidation processes.

Short-term decanting isn't a substitute for a decade of aging.

-Paul W.

You're right in relating the aging of wine to oxidation, but that's only part of the story. People who've looked into the question find that there are two different aging mechanisms: aerobic and anaerobic. As the names imply, the anaerobic mechanism will occur in the absence of oxidation. This view is supported by the empirical observations that wines recovered from the sunken Titanic and those in sealed glass ampules both have been found to mature, albeit at a slower pace. I don't think that anyone has been able to identify specific flavors associated with either mechanism, though.

Mark Lipton

Thanks for your thoughts. I am just trying to put bottle aging in perspective to get some, albeit subjective, feel for the differences between the two processes, especially in terms of flavor. Your comments have been quite helpful.

Thanks again.

Greg

Hi Mark,
I'm a wine noob and have a question regarding anaerobic aging.
I've recently read that natural cork allows gases to move into and out of the bottle. This slowly adds oxygen (air) to the wine and lets out other gases, some undesirable.
I'm probably confusing my chemistry and biology, but I thought that anaerobic processes needed the complete absence of oxygen.
Can you explain further?
Thanks in advance,
Mike-

The problem here Mike is that natural cork does not allow a fixed amount of oxygen in the bottle. It has a variable oxygen ingress rate. At times it can let in a “significant” amount of oxygen and at other times almost no oxygen (has a very tight seal on the bottle). Is this a good thing or bad thing? Tell you the truth I really don’t know. Does this play a role in the aerobic and anaerobic phases of bottle aging?

Salute

Hi Mark,
I'm a wine noob and have a question regarding anaerobic aging.
I've recently read that natural cork allows gases to move into and out of the bottle. This slowly adds oxygen (air) to the wine and lets out other gases, some undesirable.

What Victor said.

I'm probably confusing my chemistry and biology, but I thought that anaerobic processes needed the complete absence of oxygen.
Can you explain further?

Anaerobic literally means "without oxygen." Many anaerobic organisms and reactions are indifferent to the presence of oxygen, rather than being intolerant of oxygen, though some anaerobes (such as HIV) do require the absence of oxygen.

Mark Lipton