Today I've been bottling a 'Magnum Medium-Dry White' 30 bottle wine kit I've made (cheap kit, but I'm just getting back into the hobby), and I got 27 full 0.75 litre bottles out of it (20.25 litres), plus a partially filled bottle of only about 100ml of clear wine (total = 20.35 litres). I also poured the wine that had got cloudy and stirred up from the sediment at the bottom of my Hambleton Bard 5-gallon plastic fermenter during syphoning into a glass demijon to clear again in the hope that I can eke out a bit more from it. The liquid in the demijon is about 1.2 litres, of which I think I'll get about 700-800ml more clear wine out of when the sediment settles, which should make it 28 bottles in total.
The kit came as 1.7Kg can of concentrate, called for 3.5Kg of additional sugar and water to be topped up to 22.5 litre level on the level indicator on my fermenter. I'm sure I went a bit over think the 22.5 litre level to about 23 or 23.5 litres because I knew of the losses due to syphoning off the sediment. So this got me wondering about why I've only got about 28 bottles out of the kit, and not 30. I did consider that the litre/gallon level indicators on my Hambleton Bard 5-gallon plastic fermenter aren't very accurate, but they are embossed into the plastic rather then screen printed on the side, so I would think they are not far off.
I also started thinking about the chemistry of the fermentation as sugar is converted to alcohol, releasing C02:-
C6H12O6 ====> 2(CH3CH2OH) + 2(CO2) + Energy (which is stored in ATP)
Sugar ====> Alcohol + Carbon dioxide gas + Energy
(Glucose) (Ethyl alcohol)
As the C02 is given off into the atmosphere through the airlock, that means mass is being lost from sugar in the must you start with, and hence the final volume of wine you get. It's a long time since I did chemistry at school, but I did try to calculate the losses using the molecuar masses of the elements involved in the above chemical equation
C-carbon = 12.01 g/mol
H-hydrogen = 1.008 g/mol
O-oxygen = 16 g/mol
By my reckoning, sugar C6H12O6 = 180.156 g/mol; alcohol 2(CH3CH2OH) = 92.136 g/mol; 2(CO2) = 88.02 g/mol. (92.136 + 88.02 = 180.156, checks out)
That means the carbon dioxide lost represents 88.02 g/mol from the 180.156 g/mol sugar, which is 48.8 % lost mass.
Lets say the total sugar in the must was 4.5 Kg (1 Kg in the 1.7 Kg tin of concentrate, plus 3.5 Kg granulated sugar added as per instruction), then 48.8% = 2.196 Kg.
Estimating 1g = 1ml, that makes about 2.196 litres of volume lost due to C02 release. That could explain why I'm only getting 28 bottles rather than 30.
The thing is, they don't warn about this in the instructions, do they? They should tell you to compensate by topping up to say the 25 litre level if you really want the 30 bottles the kit claims it produces.
Please correct my chemistry, methodology or calculations if I've got anything wrong, which I suspect I might have.
The kit came as 1.7Kg can of concentrate, called for 3.5Kg of additional sugar and water to be topped up to 22.5 litre level on the level indicator on my fermenter. I'm sure I went a bit over think the 22.5 litre level to about 23 or 23.5 litres because I knew of the losses due to syphoning off the sediment. So this got me wondering about why I've only got about 28 bottles out of the kit, and not 30. I did consider that the litre/gallon level indicators on my Hambleton Bard 5-gallon plastic fermenter aren't very accurate, but they are embossed into the plastic rather then screen printed on the side, so I would think they are not far off.
I also started thinking about the chemistry of the fermentation as sugar is converted to alcohol, releasing C02:-
C6H12O6 ====> 2(CH3CH2OH) + 2(CO2) + Energy (which is stored in ATP)
Sugar ====> Alcohol + Carbon dioxide gas + Energy
(Glucose) (Ethyl alcohol)
As the C02 is given off into the atmosphere through the airlock, that means mass is being lost from sugar in the must you start with, and hence the final volume of wine you get. It's a long time since I did chemistry at school, but I did try to calculate the losses using the molecuar masses of the elements involved in the above chemical equation
C-carbon = 12.01 g/mol
H-hydrogen = 1.008 g/mol
O-oxygen = 16 g/mol
By my reckoning, sugar C6H12O6 = 180.156 g/mol; alcohol 2(CH3CH2OH) = 92.136 g/mol; 2(CO2) = 88.02 g/mol. (92.136 + 88.02 = 180.156, checks out)
That means the carbon dioxide lost represents 88.02 g/mol from the 180.156 g/mol sugar, which is 48.8 % lost mass.
Lets say the total sugar in the must was 4.5 Kg (1 Kg in the 1.7 Kg tin of concentrate, plus 3.5 Kg granulated sugar added as per instruction), then 48.8% = 2.196 Kg.
Estimating 1g = 1ml, that makes about 2.196 litres of volume lost due to C02 release. That could explain why I'm only getting 28 bottles rather than 30.
The thing is, they don't warn about this in the instructions, do they? They should tell you to compensate by topping up to say the 25 litre level if you really want the 30 bottles the kit claims it produces.
Please correct my chemistry, methodology or calculations if I've got anything wrong, which I suspect I might have.