Final gravity calculations?

[Ty520]

I'm more accustomed to mead,but have been getting intro country wine. Are there any calculators for country wine making that will allow you to determine a relatively accurate final gravity of a country wine based on your fruit choice and quantity akin to the kinds of information available for building a mead batch?

 

[BernardSmith]

Hi Ty520 - and welcome. Not entirely sure I understand your question. As a rule of thumb I generally assume that most fruit I ferment will produce juice at around 1.040 -1.050 (or about 1 lb of sugar to a gallon of the juice). If you are using two or three pounds of fruit per gallon and are not expressing a significant amount of juice I generally treat the fruit as relatively inconsequential in terms of the alcohol produced FROM the sugars in the juice and treat the fruit as source of flavor, color, acidity and tannin (the last two may be quite limited or very exaggerated).
If you adopt my rule of thumb, then you might add a little less sugar than you think your wine is going to want (that might be an aim for say a starting gravity of 1.090), dissolve that sugar with the fruit (and water) and take a gravity reading. If it is not close enough to 1.090 then add more sugar. If it is significantly beyond 1.090 you may want to add more fruit and/or more water. A starting gravity of 1.090 will potentially finish at 12% ABV and 12% for a country wine is typically good for balancing flavor, mouthfeel, acidity,tannins and alcohol.

 

[Ty520]

from my experience and research, based on the typical quantities of sugar and fruits used, country wines always go fully dry. I'm guessing because the sugars run out before max potential abv of the yeast is achieved?

my goal is to to be able to accurately and predictably ferment an off/demi by being able to calculate my fruit and sugar contents up front with no need to backsweeten.

perhaps a real world exercise woudl help?

for my blackberry wine, i would use the following recipe:

4 lb blackberries
2-1/4 lb granulated sugar
1/2 tsp pectic enzyme
1/2 tsp acid blend
Kmeta
7 pts water
wine yeast

i typically end up with a medium bodied, dry wine, around 0.990 - it perceives a bit sweeter, and i thoroughly enjoy it

but many friends and family prefer a bit sweeter - something intended more as a social wine for a broader audience.

So if I am interpreting what you've stated correctly, even if I added another 2# of blackberries, I'd just still end up with full bodied wine, and negligible change to abv, so all my adjustments would be to sugar...

in that case, adding another ~quarter pound of sugar would just get me to 14% abv but still be dry because we hadn't yet reached the yeast's max potential abv correct?

so if I am shooting for a 1.010 wine, I'd need to add yet another ~0.2# sugar on top of the extra 0.25# to retain residual sugar

so i'd adjust my initial recipe to be 2.7# sugar to end up with a semi @ around 1.010?

But, it sounded like per your experience, by taking the abv up to 14%, i might be compromising the balance of it? so perhaps taking the fruit content up to 6# of blackberries and going with a more heavy-bodied wine would help restore that balance?

 

[BernardSmith]

Others may disagree, but if you are aiming for a specific final gravity, you ferment bone dry, stabilize and then back sweeten to the sweetness you want. YOU , not the yeast are in the driving seat. The tolerance for alcohol that a lab publishes is like the tolerance for a load that a chain or rope maker lists. That listed tolerance is likely to be well below the POSSIBLE tolerance and centered around the TYPICAL failing load, but as with a climbing rope, if the breaking strain was listed at 1000 lbs and you applied 2000 lbs it's POSSIBLE that the rope will not fail. Possible, but not likely. BUT if you applied 1200 lbs and it did fail then good luck arguing in court that the rope should have held up. The information about yeast tolerance is informational and not absolute. A yeast that WILL tolerate up to 15% might sometimes pull 18% and may rarely but occasionally fail at 14%. If you make wine with that yeast you know that you can hit 13% without many problems.. But as with driving a car. You use your brakes to stop and you don't depend on the fuel running out to bring you to a complete stop.

 

[Ty520]

Others may disagree, but if you are aiming for a specific final gravity, you ferment bone dry, stabilize and then back sweeten to the sweetness you want. YOU , not the yeast are in the driving seat. The tolerance for alcohol that a lab publishes is like the tolerance for a load that a chain or rope maker lists. That listed tolerance is likely to be well below the POSSIBLE tolerance and centered around the TYPICAL failing load, but as with a climbing rope, if the breaking strain was listed at 1000 lbs and you applied 2000 lbs it's POSSIBLE that the rope will not fail. Possible, but not likely. BUT if you applied 1200 lbs and it did fail then good luck arguing in court that the rope should have held up. The information about yeast tolerance is informational and not absolute. A yeast that WILL tolerate up to 15% might sometimes pull 18% and may rarely but occasionally fail at 14%. If you make wine with that yeast you know that you can hit 13% without many problems.. But as with driving a car. You use your brakes to stop and you don't depend on the fuel running out to bring you to a complete stop.

In that case, do you recommend backsweetening with must, or syrup?

 

[BernardSmith]

Back sweeten with concentrated juice from the fruit you are fermenting, or with simple syrup or with sugar or honey or maple syrup or agave or whatever sweetener you wish. The more liquid you add with the sugar the more you are diluting the flavors of the wine and the more you are lowering the ABV. As I wrote , you are in the driving seat. This is your wine. It needs to satisfy you.

 

[Ty520]

I'm guessing i need to hit it with sulphites to avoid restarting fermentation?

 

[cmason1957]

I'm guessing i need to hit it with sulphites to avoid restarting fermentation?

Sulphites alone will not prevent restarting fermentation. You have two choices 1) potassium sorbate, use the proper amount for your ABV and you wont' get off-tastes that some talk about. 2) Sterile filtration and that means 0.45 (or tighter some claim) absolute filtering (the tighter the filter, the more the cost goes up).

 

[salcoco]

potassium sorbate along with k-meta is used to prevent fermentation from restarting. the best to do is ferment dry then do bench trials. I use a sweetener made from two cups sugar to one cup hot water mix in a blender . let cool. take 1/4 cup samples of wine, add 1/4 tsp in first , twice this in second three time this in third etc. do taste test find the one you like and then calculate the larger amount for the main batch. as stated the tolerance on yeast is just information as an example EC1118 is 18% I have run it up to 21% more than once.

 

[reeflections]

...potassium sorbate, use the proper amount for your ABV

This is the first I've heard of this. I always thought it was just a per/Gal measurement. Is there a formula for choosing the amount of sorbate according to ABV?

 

[Ty520]

Sulphites alone will not prevent restarting fermentation. You have two choices 1) potassium sorbate, use the proper amount for your ABV and you wont' get off-tastes that some talk about. 2) Sterile filtration and that means 0.45 (or tighter some claim) absolute filtering (the tighter the filter, the more the cost goes up).

right - but wouldn't the Kmeta added up front still be present?

 

[reeflections]

... I use a sweetener made from two cups sugar to one cup hot water mix in a blender . let cool. take 1/4 cup samples of wine, add 1/4 tsp in first , twice this in second three time this in third etc. do taste test find the one you like and then calculate the larger amount for the main batch.

After reading about this method in another post here, my wife and I sat down to 4 different wines we were about to bottle and did this. I think it was the most fun thing in the whole process of wine making. Thanks!

 

[salcoco]

sorbate and k-meta additions are by volume

 

[cmason1957]

Sorbate addition by ABV - this website indicates that ABV also influences how much Potassium sorbate to use - Potassium Sorbate.

I also read about this in winemaker magazine, by the Wine Doctor.

Assuming that proper levels of free SO2 are maintained and the pH's are within the desired ranges, sorbate additions can be determined by the estimated alcohol of the wine. The following table is based upon the percentage of alcohol in the wine:

% alcohol​	sorbate addition​
10​	0.20 g/l​
11​	0.17 g/l​
12​	0.135 g/l​
13​	0.10 g/l​
14​	0.07 g/l​

As can be seen, the amount of sorbate decreases as the alcohol level increases. This may be due to two reasons: 1) At the lower alcohol levels, there May be a greater volume of viable yeast cells; and 2) The higher alcohols may have an inhibiting effect on refermentation.

 

[cmason1957]

right - but wouldn't the Kmeta added up front still be present?

No, most of the Kmeta that was added at the beginning has become bound up and doesn't provide any oxidation protection.