Maths

[bquiggerz]

Hello,

Does anyone have the maths needed to know how much sugar to add to get to a target s.g. I'd prefer a explanation rather than it being done for me so I can do do it myself in the future.

Thanks,

Ben.

[jack_c]

Maybe http://www.brewersfriend.com/chaptalization-calculator/

[bquiggerz]

Thanks jack, I'll keep that in mind. Should have mentioned that I'd prefer it in grams and I don't have a brix thing.

[jack_c]

Brix to Gravity (and vice versa) http://www.brewersfriend.com/brix-converter/.

28g to an ounce, 16 ounces to a pound.

Careful, the calculator using them dodgy American gallons (1 US gallon is 0.832 Imperial Gallons)

[bquiggerz]

Thanks!!! That will have to do. If there are any Mathematicians here I would love too see the maths behind this.

[jack_c]

http://www.grapestompers.com/articles/c ... e_wine.htm talks through how to work it out. Careful of them American weights n measures though

[bquiggerz]

Thanks jack, very helpful

[oldbloke]

There's a chart at http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm that I like to look at occasionally
Mostly though I work on desired ABV and use the rule of thumb that 20g sugar per litre gives 1%

[bquiggerz]

Thanks oldbloke

[vacant]

1 US pound = 454g, 1 US gallon = 3.79 litres
Sugar ferments to 50% alcohol and 50% Carbon Dioxide by weight
Weight of alcohol = 227g, volume = 288ml

288/3,790 = 7.6%. Quite a difference from the 5.8%entry in the grapestompers table, I don't know why.

[oldbloke]

There's debate about what weight of alcohol you get from a given weight of sugar. It depends on a variety of factors. It can be as low as 43%.
Some good stuff on this on brsquared
One major factor is that some sugar is used by the yeast to grow more yeast rather than to make alcohol