Which colour glass would you prefer for VP?

[Tom Archer]

I believe the IVDP only requires that VP be bottled in dark glass, and that the opacity of the glass is not specified.

I personally have a strong dislike of bottles that are wholly opaque and am annoyed when I have to struggle to discern the level in a bottle..

..but who cares what I think?

Which colour glass would you prefer?

Tom

[David Spriggs]

I totally agree. I buy all the time in the UK and when I ask about levels, they generally say, we don't know. They expect that you should be able to see them in the photo from the bonded storage - it works fine for Bordeaux... but not Port. So many times I just have to guess based on how the capsules look. AQlso, when triaging Ports that I have I want to drink the low fills first. What a pain to figure out! Of course it's no problem with many of the pre-1974 UK bottings that used the green glass.
-Dave-

[Roy Hersh]

Tom,

Would you please add as an option to your poll ... charcoal black (translucent) that some shippers have already moved to. Thanks!

[Andy Velebil]

I like the dark brown, which is almost black unless you look closely. Seems to be the best all around for reducing light transmissions and still being able to easily see levels with any decent flashlight (torch).

As for the color, several years ago I attended a beer seminar and was amazed to learn how much the glass color really can affect the contents inside. Darker is the best to prevent damage from many different types of light sources. And although i don't recall the specific times it takes to be damaged, I do recall it wasn't that long if left in direct sunlight or other types of indoor lights. Obviously a dark cellar is best, but nowdays most people don't have that option. so I can see why they use the black glass....but a happy medium has to exist. Even with my super strong work flashlight I've had problems trying to see into a bottle that is dark black. :help:

[Tom Archer]

Even with my super strong work flashlight I've had problems trying to see into a bottle that is dark black.

I've tried a range of methods to see through the darkest bottles - even lasers..

Best method I've found to date is a regular 40w lightbulb with a clear bulb - not frosted glass.

Hold the bottle close to the bulb in a room that is otherwise not too bright, and study the filiament of the lightbulb through the bottle from a distance of about one foot.

Despite that, about 8% of my cellar is in bottles that are too dark to discern the level..

It might be possible to create a level detector using ultrasound technology, or fashion a probe that could detect the reduced resonance of glass that has fluid behind it.

But the better option is to drum home the message that good cellar management requires that bottle levels can be checked, so that the weaker bottles can be selected for consumption.

Its not rocket science, or unique to port..

It's really quite surprising that the producers ever contemplated using wholly opaque glass..

Tom

[Eric Menchen]

As for the color, several years ago I attended a beer seminar and was amazed to learn how much the glass color really can affect the contents inside. Darker is the best to prevent damage from many different types of light sources. And although i don't recall the specific times it takes to be damaged, I do recall it wasn't that long if left in direct sunlight or other types of indoor lights.

In beer, light reacts with isohumulones that come from hops. These break down into free radicals that hook up with sulfur from beer proteins to produce mercaptans, giving the skunky taste. I don't think you'll find isohumulones in wine, and I'm doubtful about the proteins (they come from the malt), so I don't think this particular issue applies. That's not to say that there aren't other things in wine that will degrade in sunlight. My informal experience suggests there are, but I haven't controlled for other storage conditions.

The sunlight-beer thing can happen quickly. For one of my beer classes on flaws, we doctored about 20 or so bottles with various different chemicals to taste the different off-flavors. For the mercaptan thing, the instructor just put some Corona (clear bottle) on a window sill for a few hours before that lesson.

I prefer to be able to see the fill level. To protect against light damage I like a darker bottle, but that's really for transient conditions as I store all of my bottles out of the sun.

-Eric

[Andy Velebil]

I've also been told that light does affect wine to. I don't know the chemistry behind it, but I'm sure someone here can shed some light on it.

[Roy Hersh]

In the Port Basics area, I started a thread which included an article on how light and heat can affect wine.

[Nikolaj Winther]

Tom, have you tried using a nightsight or a thermal scope/goggles? at least on the thermas scope it may be possible to discern the level on account of difference in temperature between the part of the bottle that's in contact with the wine and the part that isn't.

[Mahmoud Ali]

From a purely aesthetic point of view I like the black opaque bottles. However, like with wines I do want to see if a bottle in the cellar has developed a low fill so that I know which one should be opened. Dark bottles that allow one to see the fill level would help when decanting and would also come in handy when trying to assess the condition of an older bottle at auction or on a store shelf.

Cheers...........Mahmoud

[Tom Archer]

Tom, have you tried using a nightsight or a thermal scope/goggles? at least on the thermas scope it may be possible to discern the level on account of difference in temperature between the part of the bottle that's in contact with the wine and the part that isn't.

In an environment that is otherwise temperature stable, such as a cellar; a liquid will only be cooler than its surroundings if it is in the process of evaporating, which is not the case whilst inside a sealed bottle.

There would therefore be no temperature difference that could be revealed by the use of a night sighting device.

If the neck of the bottle were briefly warmed with a hot damp cloth, the part that had fluid behind it would cool faster as the fluid assisted the dispersal of the heat.

In theory, this could produce a visible distinction if viewed through an infrared imaging device. However, the boundary between filled and unfilled neck would almost certainly emerge as a blur, and it would be very difficult to get a clear indication when levels were close to the base of the neck.

My plan for dealing with these bottles is to weigh them, using a laboratory balance that is accurate to 0.1g, and then periodically re-weigh them to calculate the fluid loss rate. A bottle can lose upwards of 1g a year without being seriously compromised, and few bottles will lose less than 0.2g per annum - so the winners and losers from a case should be fairly easy to tell apart.

Tom

[Eric Menchen]

I don't have a scale that accurate, just to the nearest gram. Neat idea. Now I understand Tom's avatar a little more.

[Tom Archer]

The ullage rates I mentioned were quoted to me a long time ago as being typical for Bordeaux. A quick calculation suggests to me that port ullage is actually quite a lot less if the bottles are well cellared - more likely to be in the range of 0.1g to 0.5g p.a.

Tom

[Glenn E.]

Now I understand Tom's avatar a little more.

Oh, there's more to it than that. Let's just say his avatar is very appropriate!

[Tom Archer]

Well, the vote result is pretty decisive - dark brown glass than CAN be seen through is the clear favourite, although I personally voted for green.

I hope the producers take note..

Tom

[Glenn E.]

I voted for the olive green as well. For me, the dark brown glass bottles are too difficult to see through. I like to be able to just hold the bottle up in order to check the level, and you really can't do that with the dark brown glass bottles. The dark-ish olive green ones, though, let enough light through that it is possible to check the level in this manner.

[Moses Botbol]

The green is pretty. I do like to see the wine inside. The Niepoort Garrafeira is the best green bottle. The rippled surface is pretty unique. Green looks nice once empty, but I would think it does allow more sun damage than a totally black or dark brown bottle.