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How much alcohol % does 100g of dectros add to 1 litre

  • 01-12-2014 11:07PM
    #1
    TheDuke
    Registered Users, Registered Users 2 Posts: 419 ✭✭


    Hi all,

    I'm sure this has been asked many times but much alcohol % does 100g of dectros add to 1 litre - I'm just looking for the rough ratio.

    My research has it a 5% (not that that makes sense in real life - i get that)

    Thanks,

    The Duke


Comments

  • #2
    Paz-CCFC
    Registered Users, Registered Users 2, Paid Member Posts: 1,529 ✭✭✭Paz-CCFC


    I got roughly 3.4%

    The chemical reaction of sugar to alcohol is: C6H12O6 = 2C2H5OH + 2CO2.

    So, one mole of sugar creates two moles of alcohol. One mole of sugar = roughly 342g, so 100g = 0.292 moles. So, it creates 0.584 moles of ethanol. One mole of ethanol is just over 46g, so this reaction creates 26.864g of ethanol. Ethanol has a density of 0.789 g/cm3, so that's 34.048ml. So, that in 1,000ml of solution = roughly 3.405%. That's the theoretical yield, anyway.

    But, I think dextrose has 95% fermentability (compared to 99%+ of table sugar). So, that would reduce it to about 3.2%, maybe?


  • #3
    oblivious
    Registered Users, Registered Users 2 Posts: 4,381 ✭✭✭oblivious


    Paz-CCFC wrote: »
    I got roughly 3.4%

    The chemical reaction of sugar to alcohol is: C6H12O6 = 2C2H5OH + 2CO2.

    Table sugar is a dimer of Sucrose and fructose =C12H22O11: 342g

    Dextrose or D glucose is=C6H12O6: 180g
    Paz-CCFC wrote: »
    But, I think dextrose has 95% fermentability (compared to 99%+ of table sugar). So, that would reduce it to about 3.2%, maybe?

    Both should be 100% fermentable, but the sucrose is going to be needed to be broken down first by the enzyme invertase to release glucose and fructose.

    From a brewing prospective sucrose has a potential of 1.046 or 4.6% denser that an equivalent volume of water.

    100g/L of sucrose will give a specific gravity of around 1.038 and if this fully ferments out (1.000 FG) then this will give by volume around 5% alcohol (38-0/7.46).


  • #4
    loyatemu
    Registered Users, Registered Users 2, Paid Member Posts: 16,438 ✭✭✭✭loyatemu


    Brewmate reckons 4.99% for 100g of Dextrose in 1L (& exactly the same for Cane Sugar).

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  • #5
    oblivious
    Registered Users, Registered Users 2 Posts: 4,381 ✭✭✭oblivious


    loyatemu wrote: »
    Brewmate reckons 4.99% for 100g of Dextrose in 1L (& exactly the same for Cane Sugar).

    "Oh, I forgot to er, carry the one." :p

    unlock_professorfrink.png


  • #6
    TheDuke
    Registered Users, Registered Users 2 Posts: 419 ✭✭TheDuke


    Holy sh... where did you guys find your brains... Me mere mortal googled it...

    Good to hear the ratio works....


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