Looks like we messed up.
Our red must has tested at just over 1.008 on the hydrometer and 5 on the Brix scale. That won't get us to the right alcohol content - too low. We should have added sugar to the must at the first stage but we didn't.
When making wine, the Start Gravity should be 1.070 (normal finished ABV will be 10.5%) to 1.090 (normal finished ABV will be 13%). Finish Gravity should be 0.990 (for dry wines) to 1.005 (for sweet wines).
Alex made a simple sugar syrup dissolving sugar in boiled water. We have to wait for it to cool to room temperature.
Now we have to figure out how much syrup to add. Because I had to dilute the sugar solution by half to get the hydrometer to read the SG, the specific gravity of the syrup is 1.110 x 2 or 1.220.
So to increase the SG to where the potential alcohol would be sufficient, we'd have to add 40 oz sugar per gallon or 2.5 lbs per gallon. That would be 1 l of water or 1.5 l of syrup. (Alex did the maths.)
Just as a note to self: 3 kg water plus 3 kg sugar = 1 demijohn.
So we expanded our two demijohns to three with the sugar syrup and must (stirred to keep the yeast equal) divided equally among the three. I tested the SG of the resulting must and it read SG 1.070. That should get us to over 9% ABV.
Curiously, I just measured the SG of the Solaris must, and it, too, reads 1.008. Not surprising as it started out at the exact same SG as the Rondo must. So we'll have to repeat the procedure for the white.
So we have 1.5 l of Solaris must, measured by weight. So if we need 40 oz sugar per 3.78 l above, we need:
40/3.78 = x/1.5 = 15.9 or 16 oz of sugar. We added 16 oz of sugar dissolved in 16 oz of water to the 1.5 l of must and essentially doubled the volume. The SG read 1.082, a little higher than the red but perfectly fine.
Let's hope we have restarted the fermentation. At least we now have 1/3 more wine to bottle.
Here are 10 more things that can go wrong in fermentation.
https://www.brewersfriend.com/abv-calculator/
