SkiSickness

Last year we had a bumper crop of apricots here and I made wine. It did not go perfectly, but the results are quite quaffable. I took some notes but eventually misplaced them. So, this year, it makes sense to keep better notes here. Ingredients mixed yesterday:

-approximately 10 lbs of last year's apricots from the freezer
-very close to 10 lbs of cane sugar
-enough water to give ~3.3 gallons total
-1.5 tsp pectic enzyme
-2 tsp acid blend
-3 campden tablets

Before adding 5 grams of wine yeast tonight, I measured the specific gravity and it was 1.138, corresponding to a likely final ABV around 18%. The yeast is LALVIN K1-V1116 saccharomyces cerevisiae from Montreal, Quebec.

The effective chemical reaction created by the yeast is

C6H12O6 >> 2C2H5OH+2CO2

I am going to take some aside to drink with natural carbonation before it's fully dry (again).

The density of air, which is mostly N2, is about 0.00116 g/cc. Let's assume that we fill a robust enough soda bottle half full with still-fermenting wine with the intention of letting it get to a pressure of 5 atmospheres. The corresponding density of N2 would be 0.0058 g/cc.

If we only fill the bottle half full, then we would need twice the density, but there are two molecules of CO2 in the products, so that returns us to the previous density.

Finally, we convert from the mass of N2 to the mass of C6H12O6 with a factor of 180.0/28.0 ~ 6. This gives a specific gravity of 6*0.0058 ~ 0.035. This is all very approximate but I will aim to put some wine aside when I measure a specific gravity of 1.04 then see how it goes.

Tonight, the yeast is very active. Just measured a specific gravity of 1.13.

Specific gravity appeared to have increased this evening, but the characteristic smell is there along with lots of bubbles, so it is clearly actively fermenting. I am attributing the increase either to temperature or undissolved sugar at the bottom of the bucket dissolving between measurements. Going to wait two days to measure again.

Waited until this morning, measured again, specific gravity is now 1.1 flat, so we are in the 5% ABV vicinity. Will look at it again tomorrow night...

Measured the specific gravity again yesterday around 5 pm. The specific gravity was 1.09, so we are past 6% ABV.

As of this morning, specific gravity 1.078, so we are looking at more than 8% ABV now!

This morning, the specific gravity is close to 1.07, ABV should be about 9%. I am hoping by Sunday night it will be more than 10% and I will take some aside.

This morning, measured the specific gravity at 1.06, ABV should be past 10%. Filled 2/3 of a 2L soda bottle for future fizzy fun.

If SG 1.035 in a 1/2 full bottle gave 5 atmospheres, this should give 5 x (6/3.5) x (4/3) or about 12 atmospheres. This would correspond to 180 psi, just above most estimates of when a 2L bottle will burst. At some point, I'll put it in the fridge, which will stop fermentation and keep the pressure lower.

I also put an airlock on the big bucket this morning. Tonight, a bubble of CO2 bursts through it about every 30 seconds. The 2L bottle is beginning to feel pressurized.

What were the final results of this study?