Any other way to check ABV?

[ElaineE]

I forgot to recheck SG after adding more sugar before fermention. How can I work out now what my wine is now?

 

[day_trippr]

If you took the original SG before pitching you can add the sugars to that.
There's likely a better tool for this but you can work this one "backwards" to figure out your adjusted "original SG"...

https://www.brewersfriend.com/chaptalization-calculator/
Cheers!

 

[ElaineE]

Yes, original recorded but added sugar as brix too low, and forgot to check sfter sugar added., which was 750g. Usually remember... only have 30 demijohns on the go

 

[doug293cz]

Yes, it is possible to calculate the new Brix/Plato from the starting Brix/Plato, original volume, and the amount and type of added sugar. Brix/Plato is just weight % sugar in water. The general approach is:

If you have original reading in Brix/Plato, convert it to SG using the formula:

SG = 1+(plato/(258.6-((plato/258.2)*227.1)))​

If you have original reading in SG, convert it to Brix/Plato using the formula:

Brix/Plato = (-1*616.868)+(1111.14*sg)-(630.272*sg^2)+(135.9975*sg^3)​

​

Calculate the weight of the starting must/wort from the volume and SG:

If working in gal & lb, then weight = gal * SG * 8.33 lb/gal​

If working in kg & L, then weight = L * SG * 0.9982 kg/L​

(densities are for water at 68°F / 20°C)​

​

Calculate the weight of sugar in the original must/wort using the formula:

Wt of sugar = Brix/Plato * wt of must/wort / 100​

​

Calculate the modified Brix/Plato using the formula:

New Brix/Plato = 100 * (Wt of original sugar + wt of added sugar) / (wt of must/wort + wt of added sugar)​

​

Calculate the modified SG using the formula:

SG = 1+(plato/(258.6-((plato/258.2)*227.1)))​

​

If you add something other than table sugar (sucrose), then you need to adjust the weight by multiplying by the extract potential of your sugar divided by the extract potential of sucrose.

Brew on

 

[ElaineE]

Thanks. Will try this

 

[bernardsmith]

Basically, you added 750 g (total?) sugar. that is equivalent to adding 1.65 lbs of sugar. You don't tell us the volume of wine (or must) you added this sugar to, but let me assume for this calculation that it is 1 US gallon (You will divide the number we arrive at by the number of US gallons in your fermenter (assuming that 1 US gallon is approximately 4 L) Every pound of sugar dissolved in water to make 1 US gallon raises the gravity of that volume of water by 45 points (from 1.000 to 1.045) so, 1.65 lbs will raise the gravity of 1 US gallon to 1 .074 which is equivalent to 18 Brix . (if your volume is 6 gallons then divide this by 6 , so you raised the Brix by 3. If your volume is 3 gallons then divide 18 by 3 and you will have raised your Brix by 6 . Hope this is understandable and is helpful.

 

[ElaineE]

Thanks for the details. Th.is was just for 2 gallons. I have been making wine for a couple of years and currently have about 28 demijohns on the shelf! My ABV generally has been over 14% so try to cut that down by reducing sugar......

 

[doug293cz]

Basically, you added 750 g (total?) sugar. that is equivalent to adding 1.65 lbs of sugar. You don't tell us the volume of wine (or must) you added this sugar to, but let me assume for this calculation that it is 1 US gallon (You will divide the number we arrive at by the number of US gallons in your fermenter (assuming that 1 US gallon is approximately 4 L) Every pound of sugar dissolved in water to make 1 US gallon raises the gravity of that volume of water by 45 points (from 1.000 to 1.045) so, 1.65 lbs will raise the gravity of 1 US gallon to 1 .074 which is equivalent to 18 Brix . (if your volume is 6 gallons then divide this by 6 , so you raised the Brix by 3. If your volume is 3 gallons then divide 18 by 3 and you will have raised your Brix by 6 . Hope this is understandable and is helpful.

I believe the correct SG potential for sucrose is 46.2 points per pound, so than 1 lb of sugar mixed with enough water to make 1 gal of solution will have a SG of 1.0462 (I can provide the derivation, if desired.) If you add 1 lb of sugar to 1 gal of water, you will have more than one gal of solution, and the SG will be less than 1.0462.

Let's do the math:

1 gal of water weighs 8.33 lb (at 68°F)​

​

Brix = 100 * 1 lb / (8.33 lb + 1 lb) = 10.72​

​

10.72 Brix => 1.0430 SG​

​

Volume = 9.33 / (8.33 * 1.0430) = 1.074 gal​

​

This is why I recommend using the calculation method I posted above to get maximum accuracy. It takes into account the volume changes caused by adding sugar to must/wort.

Brew on

 

[bernardsmith]

I thought I wrote that you added the sugar to MAKE one gallon and not that you added the sugar TO one gallon... but I won't argue with your figures: My hydrometer is not accurate to three decimal places and when I read the scale I usually bend to read it and so the accuracy is again knocked off, while, my wine room is rarely at the same temperature as the temperature at which the hydrometer was nominally calibrated when they attached the paper scale to the glass.. 1.046 - 1.045 . OK I am a liar for 1/1000th of a gravity point. ;-)

 

[doug293cz]

I thought I wrote that you added the sugar to MAKE one gallon and not that you added the sugar TO one gallon... but I won't argue with your figures: My hydrometer is not accurate to three decimal places and when I read the scale I usually bend to read it and so the accuracy is again knocked off, while, my wine room is rarely at the same temperature as the temperature at which the hydrometer was nominally calibrated when they attached the paper scale to the glass.. 1.046 - 1.045 . OK I am a liar for 1/1000th of a gravity point. ;-)

You did get the definition correct. but then you proceeded to make calculations adding sugar to 1 or 6 gallons, which is a common mistake.

Brew on