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Comment by Gravityloss | Hacker News Reader

Cork is quite a superb material and can be used as the middle sandwich layer with carbon fiber. It's also used in space launchers as heat and noise insulator inside nose fairings. It also has ablative properties and resists flame propagation. It's lighter than most other woods, though not as light as Balsa.

So I think it's a bit of a shame that it's used for wine bottle corks and usually thrown away after use!

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To be fair, as they say it grows back in a few years and harvest doesn't kill the tree, so it's not as though they're significantly 'wasting' it. I'm sure that space programs can get all the cork they desire and more.

The cork supply is not elastic. It takes at least 20 years for a tree to mature so it can be harvested, so if the market demand is doubled tomorrow, it will take 20 years for the supply to reach demand. This increases the prices and makes recycling viable.

The video linked in the article claims they can harvest a tree every 9 years.

miahi's point was about new trees reaching the point that they could enter the 9 year harvesting cycle.

Yes. But like miahi is saying:

"It takes at least 20 years for a tree to mature so it can be harvested"

If cork demand doubles tomorrow it means you will have to plant new trees and it will take at least 20 years before those trees are mature enough to be harvested.

I was saying that if you want to start a cork supply business (grow cork trees because you see an increased demand), you'll have to wait for at least 25 years to make any cork at all, and probably 35 years to make any revenue.

A tree reaches maturity after ~25 years after planting, and the first harvest is usually low quality, so it doesn't bring money. After the first harvest it can be harvested every 9-10 years, and you can do so for hundred of years (a healthy cork oak can live for 5-600 years).

Cork does grow on trees, but slowly :).

Or wine bottlers can switch to synthetic cork (a synthetic bottle stopper) leaving natural cork to where it's needed most.

Synthetic cork has been shown not to be as 'good' as the natural type for certain cases. For one reason or another it either lets too much Oxygen through causing the wine oxidize too fast, or not enough causing wines to age slowly.

Wines that are meant to drink while young do great with a screw cap. Anything that I'd want to put in a cellar and age I'd want to have a natural cork.

I don't think its really been shown at all - this answer on Quora seems pretty balanced: http://www.quora.com/Wine/Do-wines-with-screw-caps-age-as-we...

The effects of micro-oxidization are definitely not the only change in taste that happen to an aging wine.

It's a pretty major part though. The study that I remember reading was done in Australia with white wines that had been aged for 5 years with different closures(though in the same environment). The sensory results did indicate that the choice of closure did have a pretty significant impact in the way that the wine aged. Synthetics had more oxidized notes, Screw cap wines tended to be reduced and have varietal characteristics consistent with younger wines, while cork aged as expected.

"Better" is a subjective term, and most people would actually prefer the fruitiness of a youthful wine. Heck, I know I do most of the time :) But there's something that develops with certain wines over time that I'm not just convinced that you can get with screw caps.

True

Maybe it's even part of some wine/wood interaction

Screw caps may be ok but they certainly look cheap.

I'm not convinced low-end corks are better than synthetic cork (in the case of some aging), and maybe the technology improves, leaving the solid corks to the expensive wines.

Supermarkets in France sell corks, I remember seeing them split by aging time, from 1,2 years up to around 20 years

Or screw tops. A few years back a bunch of major winemakers in Australia said "screw it, we're not using corks anymore!" (pun intended)

People told them they were crazy, that the market thought screw tops were for cheap junk wine only, but they did it. And it worked. Now only bottles going to export markets use corks.

You lose the ritual of uncorking a bottle, but it's a lot more practical to open and there is no danger of the wine being corked.

This isn't strictly true. You can get "corked" wines under screw-cap or synthetic closures but it is a lot rarer. TCA can find its way just about anywhere.

> can be used as the middle sandwich layer with carbon fiber.

I've learned a lot about FRP construction and I've never heard of cork used as a core matarial. Are you sure you're not thinking of Balsa?

Balsa is a hardwood despite being so light, so it has capillaries in it. The wood is cut into blocks and then the end-grain is pressed into the wetted-out FRP mat. The resin in the mat is drawn into the balsa through capillary action forming a very secure bond.

Manufactured foam core material doesn't have capillaries and therefore has trouble forming a bond with the resin. If you're using foam instead of balsa core, the manufacturer will specify a bonding agent that you need to use between the mat and the core.

If cork were to be used as a core, I'd think it'd have the same problem bonding with the resin as foam has, and you'd have to use a special bonding agent formulated for the cork.

EDIT: Heh, after posting I decided to google around for cork FRP core. It turns out there is a company selling a core material manufactured from cork: http://www.mcmc-uk.com/products-corecork.html; most of the users of it I can find are surfboard builders though. Here's a not-very-long thread about it on boatdesign.net: http://www.boatdesign.net/forums/materials/corecork-material...

Because cork is getting more expensive, there are spotty recycling efforts. My impression is that it's still fairly limited.

I suspect any recycling efforts will be eclipsed by the move to screw tops.

Recycling cork seems crazy. Why not just compost it?

Cork is valuable because it's fire and rot resistant, and also quite impermeable. This makes it hard to compost.

The problem is not that there ar emassive ammounts of cork filling landfills. The problem is that there is a shortage of cork to put on the wine bottles.

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