Measuring SG after Re-sweetening

Winemaking Talk - Winemaking Forum

Help Support Winemaking Talk - Winemaking Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

dcteague

Member
Joined
Dec 10, 2012
Messages
96
Reaction score
3
I have a port fermenting and I'm curious how one might calculate the final alcohol from the various SG measurements. Here is a list of my measurements:

Starting 1.098
Ending 1.004

Re-sweetened to 1.015
Ended at 1.008

Re-sweetened to 1.016
Ended at 1.000

So how would one use these to determine the final alcohol content.
 
I would calculate the total change in gravity (add up the differences) and use that for your calculation. It's not super exact but should be good enough for your purposes.

1.098-1.004 = 0.094
1.015-1.008 = 0.007
1.016-1.000 = 0.016

Total change = 0.094+0.007+0.016 = 1.017
 
Starting 1.098
Ending 1.004 13%

Re-sweetened to 1.015 1%
Ended at 1.008

Re-sweetened to 1.016
Ended at 1.000 2%

So how would one use these to determine the final alcohol content.


Not sure if this would be the correct way to calculate or not but I would say 16%
 
That's probably as close as I need to get. I just need to know how much brandy to mix in to reach 20%. I was thinking the volumes I was adding might impact the total alcohol content during re-sweetening but it looks like its not relevant - makes sense if its a percentage.
 
I am close to Winofarmer in ABV. I get about 15.5%. What volume of wine do you have now? What proof Brandy are you using? You need to know both of these numbers to compute the volume of Brandy needed.
 
I had 15.6%.

Started with ~3.25 gallons, and have added 1 gallon of liquids since through the above re-sweetening process, so I should be close to 4.25 gallons. I'm guessing I'll lose some during racking so I may put this into my 3 gallon, and save the rest for later use or just make it into a small wine batch. It'll depend on the final volume - I have 3, 5, and 6.5 gallon carboys, so if I can get this into one of them with a small amount of headroom after fortifying, that'll probably be what I use. I'm guessing it'll go into the 5 gallon and I'll have to top it off with something.
 
Ok, let's use your number of 15.6%. If you take 4 gallons of that wine you will have 0.624 gallons of alcohol in it. Put this in a 5 gallon carboy and add one gallon of 80 proof (40% alcohol) Brandy which will give you another 0.4 gallons of alcohol. Your total alcohol will be 1.024 gallons out of 5 gallons (4 gallons of wine and 1 gallon of Brandy) for an ABV of about 20.5%. Therefore, the ratio is about 4:1 wine to Brandy. If you would like to taste test this first, make up a 750 ml bottle and try it with 600 ml of wine and 150 ml of brandy.
 
Last edited:
My only concern is the volume of liquid I use to back-sweeten since I'm guessing this is going to be pretty dry when I begin fortifying. I was planning to use a concentrate - potentially blackcherry or grape (its a blueberry port). That'll probably take up another half gallon of room. I'm still thinking the 5 gallon is where I'll land. Unfortunately that's the only size where I have only 1 carboy, so when I rack for the 3rd time I'll need to make sure I've made my usual weekly trip to the brew shop for supplies. It'll give me another excuse to buy my next recipe ingredients.
 
Racked my port tonight - a bit more head room than I had hoped, but I'll fix that tomorrow since its still fermenting and I'm not yet worried about oxidation.

I'm amazed at how good this tastes already - it tasted horrible a couple days ago, it now actually taste like a wine. SG dropped back down to 1.004 so I added more juice during racking, and I'll likely rack again in another couple days, stabilize with brandy, and then bulk age for a while with oak and vanilla.
 
Back
Top