Unsweetened soy milk powder for cold water: Garuseonsaeng Seoritae
Garuseonsaeng Seoritae Raw Soy Milk Powder is an unsweetened powdered soy milk made with Korean seoritae (black soybeans) and sea salt. I mixed it with cold water at work; it was nutty and mixed well, though I could feel the skin particles and had to stir it again after settling.