Originally Posted by inkball
If i want to evaluate OG can i calculate it like this:
4kg of sugar in 10L. 1L of water is 1KG (at 4°C?), if i had only 4kg of sugar. I have 14Kg/10L so 1.40Kg/L ? I'm i right?
The reason water density is relative to 4 C is because water expands on either side of 4 C. SG measurements are typically at 15 C/60 F.
Technically 14 kg total weight in 10 total liters will have a density of 1.4kg/l, correct. However, adding 4 kg of sugar to 10 liters of water will change the final volume a bit, changing the results. something closer to 14 kg / 12 liters. Not sure if you started or ended with 10 liters.
You would want to work in degrees plato and convert. I'm not sure if you used 10 total liters, or 10 liters of water, so both would look like:
4 kg into 10 liters (10 kg) = 4 kg sugar in 14 total kg = 28 plato.
28 plato = 1.120 specific gravity which should be around the 17% potential zone.
This will have a solution volume around 12 liters.
4 kg diluted to 10 total liters requires about 7.5 liters of water
4 kg / (4 kg sugar + 7.5 kg water) = 34.8 plato
34.8 plato = about 1.15 SG, with a potential above 20%
Assuming I did that correct.
That is your starting point. So, if you had 10 total liters, you went from ~1.15 to 1.12, and I would let it keep going for a long time. I'm assuming you are using this for one of the many alcohol flavor infusions, because the "D" word will get this thread killed instantly.
In the future, you may want to use yeast nutrient, or make a starter with a huge yeast population, also hydrate in water not dump in dry. It's very possibly you could get a stuck fermentation, in which case I would add nutrient, hydrate more yeast in pure sanitized water, and re-pitch.