Is there a way to tell if dry malt is diastatic or non-diastatic?
The main difference between diastatic and non-diastatic malt is that diastatic malt has active enzymes which help break down starch into sugar.

To test if your malt is diastatic:


Take two bowls. 
Add a tbsp of flour and 2 tbsp of water for each bowl and lightly mix it. 
Then put a small amount of yeast in each bowl. Make sure they both get the same amount. 
Then put a small amount of malt powder in one of the bowls.


If the malt is diastatic, the bowl with the malt will start bubbling much earlier than the bowl without the malt. The malt will break down the starch into simple sugars which the yeast consumes. As the yeast consumes the sugar, it release carbon dioxide which are the bubbles you see.