SO2 addition?

small doses after each racking

Pp

The best method is to measure the free SO2 every month or so and make SO2 additions as needed to maintain 0.8 milligrams of free SO2 per liter of wine. Lum Del Mar, California, USA

Lum:

How does 0.8 mg/l translate to ppm?

One milligram (mg) = .001 grams One liter (l) (water) = 1000 grams One milligram per liter = .001/1000 .01/10000 = .1/100000 1/1000000 gram per 1,000,000 grams

Sorry Lum, don't think that's correct - the number is right but not for free SO2, it's molecular SO2.

For the original poster: The molecular SO2 depends on the free SO2 in the wine and the pH - to get 0.8 molecular ppm, the rule of thumb is to take the decimal point in the pH and multiply by 10 to get the required ppm (mg/L) of free SO2. Ex. pH 3.1 -> 10ppm free SO2 needed, 3.4 -> 40 ppm, etc.

Pp

You are correct Pp. Thank you for correcting my blunder. Lum Del Mar, California, USA

Just post how many campden tablets to use per gallon of wine and when to use it ;)

I wish I could Thomas. But, sulfur dioxide use is complicated and I am too stupid. Lum Del Mar, California, USA

The rule is 1 tablet per gallon. Generally, one in primary about 12 hours before adding the yeast. _Don't_ add any when transfering to secondary. Add one more at the first post ferment racking, and another when bottling.

If you do any more "in between" rackings, you may want to add 1/2 tablet at these rackings. Always crush the tablets between 2 soup spoons into a fine powder and disolve in a small amount of water before adding. If you only need 1/2 tablet, only add half the water etc.

All of this is based on the assumption that the ph of your wine falls somewhere between 3.2 and 3.6. HTH

Frederick