Backsweetening calculations? - Home Brew Forums

 Home Brew Forums > Backsweetening calculations?

04-18-2011, 04:58 PM   #1
DarthBeer

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Dec 2009
Area 52
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Does anyone know of a formula or calculator for calculating the amount of backsweetening needed to bring a cider to a given gravity?

I have a cider that has a 1.000 gravity and I want to raise it to 1.020 using apple juice concentrate. I have done it with previous batches with trial and error. Adding a little at a time and sampling after each addition to raise to the right reading. This takes time and seems to be the hard way to do it.

I'm looking for a way to calculate how much sweetening is needed and get it right the first time instead of alot of time tweaking it.

04-18-2011, 06:09 PM   #2
Almighty
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Jan 2009
San Diego, CA
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The way that I do this is all based on gravity points.
So it appears to you want a 1.020 (sounds super sweet to me) or 20 gravity points. What you need to do is measure the gravity of your concentrate or juice (most juice I have used has been in the 1.050-1.055 range). So after you mesure your gravity that will tell you how many gravity points per gal or 128 oz.
Example:
Need 1 gal of 1.000 cider to 1.020. Using 1.050 juice you would need to add .4 gals (51 oz) to get 20 pts. Or using concentrate at 1.200 you will need .1 gal (13 oz).

Also remember that this dilution will reduce your final alcohol content. For the above example the juice would give you a 29% reduction (.4/1.4) in alcohol and the concentrate would reduce it by 9% (.1/1.1).

04-18-2011, 09:54 PM   #3
DarthBeer

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Dec 2009
Area 52
Posts: 97
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Quote:
 Originally Posted by Almighty The way that I do this is all based on gravity points. So it appears to you want a 1.020 (sounds super sweet to me) or 20 gravity points. What you need to do is measure the gravity of your concentrate or juice (most juice I have used has been in the 1.050-1.055 range). So after you mesure your gravity that will tell you how many gravity points per gal or 128 oz. Example: Need 1 gal of 1.000 cider to 1.020. Using 1.050 juice you would need to add .4 gals (51 oz) to get 20 pts. Or using concentrate at 1.200 you will need .1 gal (13 oz). Also remember that this dilution will reduce your final alcohol content. For the above example the juice would give you ia 29% reduction (.4/1.4) in alcohol and the concentrate would reduce it by 9% (.1/1.1).
i think I'm missing something in the math here.
Given the cider is 1.000, and the juice is 1.050. That's a difference of 50 points. The target is 1..020 which is a 30 point difference between the target and the juice. How does either of those differences equate to .4 gallons?

04-18-2011, 10:59 PM   #4
Almighty
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Jan 2009
San Diego, CA
Posts: 428
Liked 28 Times on 21 Posts

I'm sorry I was doing that totally wrong. Below is the right equation:

(volume of fermented cider)(gravity of fermented cider) + (volume of juice/concentrate)(gravity of juice/concentrate) = (total blended volume)(blended gravity)

Ex. (easier with gravity points)
(1)(0) + (x)(50) = (1+x)(20)
50x = 20 + 20x
30x = 20
x = 20/30 = .67 gals