I have been meaning to try this, mostly because it seems more eco-friendly than because it will save me a ton of money. Thanks for the info. And I don't know about different grades of flour, but all flours are not created equal. Some flours are just dryer than others and current humidity can affect them too. At least I've found that to be true for baking, so I imagine it works for grave too. Or for glue, as the case may be!