Sugar calculation

[back2it]

Target SG of 1.070 for 10ltr of water comes out at 1.75kg sugar but when you add sugar it will increase the volume of water to 11.2ltr so will actually require 1.97kg of sugar.

Is my calculation correct?

I haven't physically checked it with a hydrometer yet, just checking my calclation.

Thanks
Ray...

 

[winemaker81]

You're over-thinking the situation.

1 lb sugar in 1 US gallon of water produces SG 1.045. Using that proportion and your figures, by my calculation you need 1.86 kg sugar. The final volume of the must is not a concern.

Winemaking has a large number of variables upon which we have no control. IME we want to have a final volume slightly larger than our secondary container size, after volume loss due to sediment.

 

[back2it]

You're over-thinking the situation.

You are right of course. I am just working on my record keeping and as it's in excel I thought I would make a lazy approach to knowing what the sugar value the contents in the must are and approximately what sugar I should add. It is of course never really accurate as if you put an apple in who knows how much sugar is in it and how much of that will be extracted, but I just want to see how accurate I am.

I need to go back and start to calculate in imperial measures again and use your figures. I think I last did that in 1971, or was it earlier 😲

12 pennies in a shilling, 20 shilling to the pound, 1/2 crowns, guineas, thruppence and sixpences Of course, living in Germany for 12 years didn't help. I now cross my sevens, follow the rules of the road and always wait at the red lights on a foot crossing.


I'll go take a chill pill now, thanks
Ray...

 

[BarrelMonkey]

I need to go back and start to calculate in imperial measures again and use your figures. I think I last did that in 1971, or was it earlier 😲

I grew up in Britain but now live in the US - There are 16oz in an American pint and 20oz in an Imperial pint but I always thought the ounces were the same - Turns out I was wrong! 1 US fl oz = 1.04084 Imperial fl oz. (I learned this over a year ago through winemaking talk - in fact I think it was a post by @winemaker81...)

Anyway, to the matter at hand: I ran your numbers through a couple of online calculators as well as a spreadsheet that I use for fruit/flower wine recipe planning. I'm assuming your total (starting) volume is 10L and starting SG is 1.000, ie all the sugar comes from what's added. The results:

Fermcalc: Add 2.056kg, result 11.27L
Vinolab: Add 1.825kg (no final volume stated but I figure it to be ~11.10L)
My spreadsheet: Add 1.95kg, result 11.17L.
And as a fourth data point, @winemaker81 above says to add 1.86kg.

My rule of thumb is that adding 1kg sugar increases the volume by 0.6L

My 2 cents (2p?) - as long as you add something in the range of 1.8-2kg, I don't think the overall structure of your wine will be far enough away from your target to make an appreciable difference.

 

[winemaker81]

@back2it, you've illustrated a point -- winemaking is an art, not a science. There are too many variables and unknowns for it to be a science.

Science is making calculated and fact based decisions.

Art is making decisions using available facts along with experience and gut feel. It helps to have mentors whose experience and gut feel teach you what to do.

Experience is a hard teacher -- the lesson comes after the test.

Keep asking questions. It's FAR easier to learn from the mistakes others.