alcohol from sugar

[gcol]

What volume of alcohol can ideally be obtained from 1kg. of sucrose? Specifically by fermentation.

 

I specify sucrose, assuming that not all sugars have the same conversion rate, and not all sugars are fermentable. (e.g. lactose).

 

This question arises from curiousity about 1. home brewing, and 2. producing alcohol as fuel. As a side issue, perhaps for another forum, I wondered 3, about the total energy input required to produce alcohol from, for example, Brazillian sugarcane. (of interest to seekers after alternative energy sources).

 

Figures are obtainable for alcohol yield per hectare of brazilian sugar cane, but not more detailed information.

[YT2095]

well with Sucrose C12H22O11 you`ll get 4 mols of Ethanol for every 1 mol of Sucrose.

 

yeast doesn`t directly use sucrose though, so it`ll break it down into Glucose 1`st, so we have C6H12O6 +H2O = 2C2H5OH +2CO2

(we`re ignoring the yeast intermediary).

[gcol]

Thanks, that's a start, gimme more!

 

P.S. Aren't mols little blind furry things that ruin your lawn?

[YT2095]

well they are yeah, and they drink your Beer!

 

as far as I can remember, making Alc fordistilling purposes (so you don`t care about the taste) it`s roughly just over 300gr of sucrose per litre of water, with a special Alc producing yeast (doesn`t die until the 20% acl mark), will produce a good 18% alc.

so for your Kilo of Sucrose, you`de get 3 litres of roughly 18% alc.

 

so if we round off nicely and go 18 X 3 =54% alc when concentrated into 1 litre, and then double that to make 108% and round off to 100, we get just over half a litre of 100% pure ethanol per kg of sugar.

 

sorry this is just off the top of my working out, but that`s about what I`de expect to get as a return

[gcol]

Cheers, thanks, I'll drink to that..

 

P.S. Aj47 has a thread about homebrew, that info seems relevant to that, too..........

[YT2095]

only if he knows what yeast/zymase he used, different strains die off at different alc levels, so the sugar content`s nothing to go on really

and even if it was taken to the "Ideal" complete fermentation, you`de still need the final volume to divide the alc into afterwards.

my guess in a demijohn, he`s still sitting on alot of unused sugar in there.