I almost had an accident with one of my 250 ml bottles of Caffenol Strong. I made one liter of Caffenol Strong, 200 g coffee, 200 g Vit.C and 100 g sulfite but I didn´t count on the formation of SO2 gas from sulfite in an acid medium like coffee plus Vit. C. In fact, I should have read about this prior to the experiment (always learning). In this Caffenol version sulfite was intended as a preservative, like used for wines. I based the ammount on developers that use sulfite as an alkali, so the amount is excessive and it will produce at room temperature, after some time, a lot of gas. Fortunately I controlled the bottle, oppening slowly and lots of gas came out. From the other 3 bottles in refrigerator, in fact, no gas came out, maybe some is present but dissolved in the solution. The colder the solution the more gas it can store. It was a good idea to store the develçopers in the refrigerator.
I don't think this version of Caffenol will last (we will see) for months without changes. The ammount of sulfite as Oxyden scavenger is measured in parts per million and not 100g/liter like I did. The next version will have just a small ammount of sulfite, very few gramms, maybe one gramm is enough.
But I discovered how to use this 'developer'. I am preparing a beverage with only 5ml/liter of Caffenol Strong in just water. The total amount of sulfite in this drink will be about 500 ppm, like in some wines. Some people have allergic reactions to sulfite, but it is present in all wines. In the USA if a wine has more than 10 ppm of sulfite that must be written on the label.
Cheers! It is a very good beverage, and healty, 1g of the anti-oxidant Vit. C in one liter.
PS - Add some sugar or honney if you like it sweet!