I'm happy this is helpful!
Sorry for not explaining the abbreviations. K-meta is Potassium (K is periodic table symbol for potassium) metabisulphite. Another thing that will confuse you is the K-meta refers to both the powder AND a sterilizing solution made with K-meta. You need context to understand which is which, e.g., you will put the powder in wine but will use the liquid to rinse equipment.
There are different recipes for the sterilizing solution -- my current one is 3 Tbsp K-meta and 1 Tbsp tartaric acid dissolved in 1 gallon/4 liters water. I keep this in a 4 liter jug, and as long as it's clear (doesn't contain chunks) and stinks, it's good. [tartaric acid is supposed to be best, but I over-purchased acid blend so I'm using that until it's gone.]
Sorbate is Potassium Sorbate. Sorbate will prevent a renewed fermentation, e.g., if the wine is not currently fermenting, adding sorbate + K-meta will prevent a fermentation from restarting. This is referred to as "stabilizing" the wine. The sorbate I have calls for 1/2 tsp per 1 gallon and K-meta is 1/4 tsp per 5 gallons added to the wine.
And yes, if you add sugar without stabilizing, the fermentation can restart. One thing that prevents this is if the ABV (alcohol by volume) is greater than the yeast's alcohol tolerance. If a yeast has a limit of 14%, when the ABV hits 14%, the yeast has effectively poisoned its own environment and stops eating sugar. Unless you make them strong by adding more sugar, most fruit wines will need stabilizing before back sweetening.
Residual sugar is the amount of unfermented sugar in a wine when bottled. I calculate it for the wines I sweeten ... but I cannot say my formula is 100% correct. Once a wine starts fermenting, the alcohol skews a lot of calculations, and higher levels of alcohol skew them more.
Take a look at my notes from my last batch of elderberry, it may help you.
Sorry for not explaining the abbreviations. K-meta is Potassium (K is periodic table symbol for potassium) metabisulphite. Another thing that will confuse you is the K-meta refers to both the powder AND a sterilizing solution made with K-meta. You need context to understand which is which, e.g., you will put the powder in wine but will use the liquid to rinse equipment.
There are different recipes for the sterilizing solution -- my current one is 3 Tbsp K-meta and 1 Tbsp tartaric acid dissolved in 1 gallon/4 liters water. I keep this in a 4 liter jug, and as long as it's clear (doesn't contain chunks) and stinks, it's good. [tartaric acid is supposed to be best, but I over-purchased acid blend so I'm using that until it's gone.]
Sorbate is Potassium Sorbate. Sorbate will prevent a renewed fermentation, e.g., if the wine is not currently fermenting, adding sorbate + K-meta will prevent a fermentation from restarting. This is referred to as "stabilizing" the wine. The sorbate I have calls for 1/2 tsp per 1 gallon and K-meta is 1/4 tsp per 5 gallons added to the wine.
And yes, if you add sugar without stabilizing, the fermentation can restart. One thing that prevents this is if the ABV (alcohol by volume) is greater than the yeast's alcohol tolerance. If a yeast has a limit of 14%, when the ABV hits 14%, the yeast has effectively poisoned its own environment and stops eating sugar. Unless you make them strong by adding more sugar, most fruit wines will need stabilizing before back sweetening.
Residual sugar is the amount of unfermented sugar in a wine when bottled. I calculate it for the wines I sweeten ... but I cannot say my formula is 100% correct. Once a wine starts fermenting, the alcohol skews a lot of calculations, and higher levels of alcohol skew them more.
Take a look at my notes from my last batch of elderberry, it may help you.