Balthazar…

NB – if you have posted comments, I often include follow up questions in my replies so do check back and read my responses.

A standard wine bottle holds 750 ml (cm³) of liquid. That is ¾ of a litre, sometimes called 75 cl. We almost always use units derived from the litre to measure volume in our science lessons. A litre is a cube of side 10 cm so its volume is 10 cm × 10 cm × 10 cm = 1000 cm³. The standard (or SI) unit of volume is the metre cubed (m³). In most of the situations we encounter, a metre cubed is rather large so we tend to record quantities like density as g/cm³ or kg/litre.

Wine bottles have their own special system for indicating the volume of liquid they contain. A double bottle is called a Magnum (150 cl), a Jeroboam (usually) contains four bottles worth and a Methuselah is equivalent to a double Jeroboam. A Balthazar is quite a large bottle as it holds 12 litres of wine. A Balthazar of Special Cuvee Bollinger Champagne in a red gift box will set you back a mere £1,180. On the upside, it should be enough to pour a glass of champagne for you and 95 of your closest friends.

The bubbles in fizzy wine come from anaerobic respiration in yeast that produces both alcohol and carbon dioxide. Champagne is wine that undergoes a second fermentation in the bottle. This is a technique pioneered by an English scientist called Christopher Merret in the mid 17^th century. He identified that adding a little extra sugar to almost any wine encouraged further fermentation. If this process occurs in a sealed environment, the carbon dioxide dissolves to produce the fizz. This required strong glass bottles and the English were good at making strong bottles. You may already have noticed that champagne bottles are sturdier than standard wine bottles and that the cork is wired on to prevent it bursting open under the pressure of the CO₂ being produced within.

The solubility of CO₂ increases with increasing pressure and decreases with increasing temperature. If you leave your coca-cola open in a warm place it will go flat very quickly. If you open your Balthazar of champagne you need to get on and drink it before it loses its fizz. You could keep it bubbly by keeping it in the fridge and sealing it again. As the liquid level drops you may need to pump carbon dioxide in to keep the concentration of CO₂ above and below the champagne the same. This will tend to stop the gas from evaporating out of the liquid. Keep the environment pressurised and your bubbly should keep its bubbles!

The alcohol and bubbles in champagne come from the action of yeast. Yeast is a fungus that occurs naturally on fruit. In oxygen-free conditions it will convert glucose into ethanol and carbon dioxide, in a process known as anaerobic respiration (or fermentation). Aerobic respiration usually produces 36 molecules of ATP (per glucose molecule) but anaerobic respiration only produces 2 ATP molecules. ATP is the energy rich molecule that cells can use for growth, repair and all their other vital processes.

Questions…

1. How many standard bottles of wine is equivalent to a Balthazar?
2. How many standard bottles of wine would you need to buy to fill a 1 m³ container?
3. Ethanol (alcohol) is a flammable liquid with the chemical formula C₂H₅OH. What two compounds are formed when it burns completely in air?
4. Roughly, what is the solubility of CO₂ at 16°C?
5. What is ATP converted into when it gives up its energy within the cell?