Is there a food-grade humectant that deliquesces at a relative humidity as low as 40%?
I would like to generate CO2 in an enclosed container (a quart or gallon) with Sodium Bicarbonate powder, Citric or Ascorbic Acid powder, and a humectant powder that will deliquesce if the RH is >40% to generate the water source. I believe Sodium Chloride does the trick and is available in a food-grade, but I am hoping to find something less caustic.