Contradictions in sugar content formulae - they can't all be right!

[James Burton]

Mathematics aside, as far as possible, how to square the sugar-to-alcohol question Here goes...

CJJ Berry* in his calculations seems to throw up some sugar related discrepancies. I know it’s an old book and it’s table seems contrary to my recipe’s instructions but surely not this wildly off the mark? Any help sorting through this web of confusion will be gratefully acknowledged.

Using a Magnum wine Kit volumes as instructed (3.5 Kg sugar plus 1.7 L concentrate grape juice) in total volume of 22.5 Litres i.e. 5 Gallons, my hydrometer is reading precisely 1075 SG. This equates, the CJJB table says, to finished ABV of a measly 9.9% - that assumes a finished SG of 100. Calculated math presuming a more realistic final SG of 998 - a drop of 77 divided by 7.36 = 10.46% - slightly bigger but still well short of a typical 12 – 13% of commercial white wine. Clearly I need to add more sugar or decrease water.

Here’s where CJJB’s table gets confusing – it says 1075 is equal to 870g of sugar IN 4.5 Litres equating to 4.35 Kgs in 5 gallons (22.5.L). But I have only added 3.5 Kgs IN 5 UK gallons – so how come I have ended up with an SG reading equivalent to (870g x 5) 4.35Kgs? Again, according to CJJB’s table, for a final ABV of, say, 13.4%, I need 1.18Kgs per gallon – in my case five times that – i.e. 5.9KGs – this is nearly twice as much as the Manufacturer (Magnum) recommends in their instructions for 5 gallons. They can’t both be right, or am I missing something here?

(*Author, 1960, First Steps in Winemaking)

 

[Gyro]

Mathematics aside, as far as possible, how to square the sugar-to-alcohol question Here goes...

CJJ Berry* in his calculations seems to throw up some sugar related discrepancies. I know it’s an old book and it’s table seems contrary to my recipe’s instructions but surely not this wildly off the mark? Any help sorting through this web of confusion will be gratefully acknowledged.

Using a Magnum wine Kit volumes as instructed (3.5 Kg sugar plus 1.7 L concentrate grape juice) in total volume of 22.5 Litres i.e. 5 Gallons, my hydrometer is reading precisely 1075 SG. This equates, the CJJB table says, to finished ABV of a measly 9.9% - that assumes a finished SG of 100. Calculated math presuming a more realistic final SG of 998 - a drop of 77 divided by 7.36 = 10.46% - slightly bigger but still well short of a typical 12 – 13% of commercial white wine. Clearly I need to add more sugar or decrease water.

Here’s where CJJB’s table gets confusing – it says 1075 is equal to 870g of sugar IN 4.5 Litres equating to 4.35 Kgs in 5 gallons (22.5.L). But I have only added 3.5 Kgs IN 5 UK gallons – so how come I have ended up with an SG reading equivalent to (870g x 5) 4.35Kgs? Again, according to CJJB’s table, for a final ABV of, say, 13.4%, I need 1.18Kgs per gallon – in my case five times that – i.e. 5.9KGs – this is nearly twice as much as the Manufacturer (Magnum) recommends in their instructions for 5 gallons. They can’t both be right, or am I missing something here?

(*Author, 1960, First Steps in Winemaking)

Not sure if I'm reading this right, but are you including the sugar that will be in the 1.7kg grape concentrate in your calculations?

 

[Chippy_Tea]

I haven't read the full thread but the supermarket juice wine recipe is 1100g sugar total in a 4.5l demijohn gives 13% ABV.

 

[MashBag]

James I think you are looking for an absolute that isn't there.

Why?
Not all sugars are not the same.
Not all sugars are fermentable
Not all measures, measure in the same way. Brix, balling etc.
Not all hydrometers are the same.
Not all temperatures are the same.
Not all yeast are the same.
... I can do a few more if you want

And if you get through all that remember yeast at organic, we don't fully understand fermentation so when the wee ones decide on 997 no amount of maths will change their mind

If you want alc content exactly, you must distill the final product in lab conditions. Anything else is just a guide. Pretty close but..

 

[James Burton]

Thank you all for your thougghts.
Yes, I assumed the grape juice concentrate would add its own sugar content, which is why, in this specific case, I waited until the final moment before I would add the yeast: so water, sugar, juice, all in.
My puzzle remains unresolved - the wine kit "usually results" in a final abv of 12-13% (kit mnfrs figures) - yet my (formerly) trusty hydrometer remains stubbornly at 1075 in the ansolutely still, bubble-free 28 degree must - I checked the hydrometer against tap and bottled water and it comes up near-zero in all cases: can it be faulty? Its the Scottish glass model.

 

[MashBag]

28c? Most hydrometers are calibrated to 20c. You can look up temp adjustment charts..... And we may solve the problem.

 

[MashBag]

Here you go...
https://www.brewersfriend.com/hydrometer-temp/

 

[James Burton]

Thanks, Mashbag - that will give me an adjusted figure of 1.077 from 1.075- on the same BrewersFriend site, a hoped-for finished gravity of 0.998 would push up my end abv to 10.37% - up from 9.9%, and so an appreciable amount. I shall take this adjustment method forward in all future measurements.
Thank you for the heads up.

I haven't read the full thread but the supermarket juice wine recipe is 1100g sugar total in a 4.5l demijohn gives 13% ABV.

From the above contributor (thanks)- total sugar content (juice 'n' all) should be 110g per 4.5L - if this is correct, my 22.5 batch is short of total sugar-iness by 5500-4350 = 1150. This broadly aligns with the CJJ Berry tables, and so, with heart in hands, I'm about to dissolve another 1.150 kilo in the must and see where we end up after a couple of weeks - hopefully not with a stuck fermentation and a sickly mess!
Once more, thanks to all

 

[MashBag]

You are better off adding sugar later. The yeast like a thinner start, and then there is a full house ready to receive your extra dose.

 

[James Burton]

Yes, I'd heard that: I was trying to ascertain the total overall amount and then withhold some to add later, but fuzzy on the procedure.
I didn't want to dilute the mash with another pre-boiled litre(s) of water to dissolve the extra sugar, and so I proposed syphoning off, say, two litres (or maybe four litres) of the mash and dissolving the 1.1kg extra sugar in that, adding it to the main body after the first flush of Aerobic fermentation has died back.
Sound good? Thanks for staying with this, appreciate it.