Wikipedia says about Amber Malt the following...
Amber malt is a more toasted form of pale malt, kilned at temperatures of 150–160 °C, and is used in brown porter; older formulations of brown porter use amber malt as a base malt (though this was diastatic and produced in different conditions from a modern amber malt). Amber malt has a bitter flavor which mellows on aging, and can be quite intensely flavored; in addition to its use in porter, it also appears in a diverse range of British beer recipes. ASBC 50-70/EBC 100–140; amber malt has no diastatic power.
What exactly does that last part mean? Does it mean Amber Malt does not give off enough sugars when boiled and is therefore not suitable for use as a primary grain?
The website I bought it from said nothing about it not being suitable as a primary grain.