Concave bottle bottoms

I think Cecil gave an incomplete answer on this topic.
OXY bottles and such have concave bottoms to help make the bottle strong enough to withstand the high pressures. They are not designed to be stacked one atop each other. An champagne bottle left in a hot car can develope quite high pressure. Why I left it in the car is none of cecil’s business. Without the concave bottom, it may have burst. Or should I say as I did when small, “It consploded, it consploded” ? <-- 3¼¢

Catbiker says:

“Consploded.” Cute!

The bottle of champaign Borghand put in the freezer and then forgot consploded also. Heat and cold both cause a build up of pressure?


Pamela
I was taught to be charming, not sincere.
-Into the Woods

Akchewlee - the reason for the concavity found on the bottoms of some wine bottles is a little less known than one might suppose. If you ever find yourself in a room with some convivial friends (having perhaps imbibed some of the contents of a few bottles) try this: Hold up a wine bottle, one with the described concavity and say…“I’ll wager that I am able to drink wine from this bottle without the necessity of removing the cork (or, God forbid, the cap), and without in any way damaging the bottle.” A glance around the room shows a small ripple of interest. Enough indeed, to proceed. Holding the bottle (with the concavity) upside-down, ask someone to pour, from another wine bottle, an amount sufficient enough to provide a healthy drink, into the concavity. Up-tilt the bottle and enjoy your drink! Moving on… I live in the “Wine Country” here in Sonoma, California and made a few phone calls, with the following concensus: There is really no reason, other than maybe simple aesthetics, or that the added weight on the bottom of the bottle would make it more stable, but no other reason! As to the possibility of its use during the “riddling” process (the procedural turning of the bottles in racks)…no so, all wine bottles, not just the ones with concavities are turned in the riddling process.

Snipped from Attitude1’s post:

I was under the impression that only spakling wines/champaigns were riddled. I saw riddling racks at Domain Chandon in Napa County, CA but none in any of the dozens of other wineries I’ve visited in Northern California’s wine country.

-Pamela
“Riddle me this, Batman!”

Uh, Cat. The fact that you left a champagne bottle in a hot car, and it didn’t explode, is not proof that that’s why the bottle has a concave bottom.

Although in winemaking, as in many industries, there’s a strong element of “we do it that way because we’ve always done it that way,” it can be stated with reasonable certainty that the concave bottom has nothing to do with helping the bottle withstand pressure. The logic here seems to be that a concave bottom, as opposed to a flat bottom, provides more surface area, and thus the pressure per square inch is less. However, as a moment’s thought will make clear, one can achieve the same result with a convex bottom, and in fact a convex bottom is subject to less stress. (You ever see a balloon that had a concave bottom?) That’s why most oxygen tanks I have seen have hemispherical bottoms. Some tanks sit in cups or liners with concave bottoms; this permits the tank to be stood upright. Look at a two liter pop bottle - hemispherical bottom, sits in a concave cup.

As for the stacking thing, this is the answer commonly given. See the Oxford Companion to Wine, p. 140, second column.

CA

Hey, what about the whole sediment thing? I was under the impression that concave bottoms on bottles helps the sediment stay in the bottle when the wine is decanted. It seems to work, although I must admit that by the bottom of the bottle, I’m not always in an observant state.

Not really… temperature and pressure are proportional to each other. however, water and things with a lot of water in them expand when they freeze, which I guess would indirectly cause a pressure if it was in something that couldn’t expand as well, such as a wine bottle.

So, why hasn’t the wine bottle design changed? They all look the same, a neck and the body, which is straight.

I would think that a donut design would be better because its easier for drunks to hold on to.

Well, if it werent for that concave bottom, I wouldn’t be able to open a wine bottle with my bare hands. Adds strength. I might add, I can do that without using any openers of any kind…Just my bare hands!..no champagene bottles, those would be too easy.

No word games here. Open the wine bottle with the bare hands–IE take the cork out of a bottle of wine. :slight_smile:

On one of those wine programs on PBS they explained that many wine bottles have a concave bottom so that the bottle may be poured with one hand so that the other hand doesn’t unnecessarily heat the wine inside.

The comment about a wine bottle having a convex bottom to likewise provide strength to the bottle - well, I guess that would work too, only you could not make a one-piece design that could stand on a shelf or table by itself, thus making it more expensive to produce.


The O-man.
Always do right. This will gratify some people and astonish the rest.–Mark Twain

Strength? No, because glass soda bottles [remember those] did not have the indention.

Sediment? No, because sediment collects on the bottom with or without it. However, red wine must be poured label up as that way the sediment stays where its supposed to.

I vote for balance. Big bottles balance better with those indentions. Small ones, like the soda bottles don’t need them.

Uncle Cecil writes,
)))Uh, Cat. The fact that you left a champagne bottle in a hot car, and it
didn’t explode, is not proof that that’s why the bottle has a concave
bottom.

Although in winemaking, as in many industries, there’s a strong element
of “we do it that way because we’ve always done it that way,” it can be
stated with reasonable certainty that the concave bottom has nothing to
do with helping the bottle withstand pressure. The logic here seems to
be that a concave bottom, as opposed to a flat bottom, provides more
surface area, and thus the pressure per square inch is less. However, as
a moment’s thought will make clear, one can achieve the same result with
a convex bottom, and in fact a convex bottom is subject to less stress.
(You ever see a balloon that had a concave bottom?) That’s why most
oxygen tanks I have seen have hemispherical bottoms. Some tanks sit in
cups or liners with concave bottoms; this permits the tank to be stood
upright. Look at a two liter pop bottle - hemispherical bottom, sits in
a concave cup.(((((

I disagree, Cecil, I have handled and seen millons Of Oxygen Tanks and almost all (99.999%+) of them have a concave bottoms. The DOT 3AA stanards does not permit the welding on any part of the cylinder. This makes it hard to afix a stand to the bottom of a tank. Altho I will admit that I have seen a few oxy tank with hemispherical bottoms with a footring afixed to the bottom. (Linde Q’s).

TK Slaughter

"Although in winemaking, as in many industries, there’s a strong
element
of “we do it that way because we’ve always done it that way,”
Could be TK.

I bought some red wine from Trader Joe’s.
It doesn’t have a concave bottom. Maybe they quit doing this after all?

Matter of fact, the whole case of wine has
straight bottoms.

Having gone back and reread the original question from March the 5th, I would pose this question. Do “they” put sparkling and or champagne in flat bottom bottles? 3¼¢

Slightly off-topic: at least some champagne bottles are designed with weak bottoms (compared to the rest of the bottle, that is). That way, if the bottle fails under pressure, only that bottle is damaged, not the others in the rack with it. The bottom of the bottle comes off rather than the whole thing shattering.
Note: they are not likely to go boom in your cellar - this mainly happens during fermentation. The winery wants to reduce losses.

My winemaker friend points out that the concavity (called a “punt,” BTW) serves to strengthen the bottle, not against internal pressure per se, but against external trauma exacerbated by internal pressure. A wine bottle with a flat bottom is more susceptible to breakage than a concave bottom if the bottom strikes a hard surface at an angle. the form of the punt shunts the force of the impact around the sides of the bottle, minimizing the shearing force that otherwise would cause the bottom to break off. This is why punts are particularly common in champagne bottles, which tend to be wider at the base and therefore more susceptible to breakage.


Live a Lush Life
Da Chef

Say Chef, you know they hit a champagne bottle against the bow of a ship??? Well, them things usually split open pretty easily…doesn’t this show they are rather weak after all?

I’ve always considered that a barbaric practice…why not smash a bottle of waterproofing on the front of the ship and then drink the champagne?

Anyway, no glass container can be made proof against deliberate malice (like the ship ceremony, or the way some tony restaurants will knock the top off a bottle of champagne with a saber tableside for that extra dramatic touch)…the punt serves to protect somewhat against accidents. Anyone who’s barely bumped a picture frame against the floor and had the glass shatter knows how important that can be.


Live a Lush Life
Da Chef

A question for all concerned: why ask vinters about the shape of their bottles? They don’t make bottles; they make wine. Anybody know a glassblower?

A question for all concerned: why ask vinters about the shape of their bottles? They don’t make bottles; they make wine. Anybody know a glassblower? ]]]]]]

Next time I go to Sliver Dollar City, visitors always want to do that, I’ll ask the glass blower. 3¼¢