What defines a base malt compared to others?

Just curious about how to tell whether something can be used as a base or not.  Is there a dividing line? I’m guessing it’s basically whatever provides the main amount of fermentable sugars, but how do you know which malts do that? I can generally tell which are base malts and which are not, but for some I don’t know.
Thanks for any help!

Basically if it can self-convert (because it has sufficient diastatic power) then it is a base malt. There may be a few exceptions to this though (victory I believe can self-convert but would not make a great base malt).

Whether it has the diastatic power to self-convert or self-convert plus convert other starches. Diastatic power refers to the volume of starch converting enzymes in the malt. Generally lighter, non-crystalized grains have sufficient diastatic power to at least self-convert while the lightest grains usually have enough enzyme to convert itself plus a considerable portion of other grains whether malted or unmalted. Unmalted grains are never base grains because they lack diastatic power or have so little that it is a meaningless contribution.

Agreed with both of those.

Approximately what would be the level of diastatic power needed for self conversion?

IIRC, >25L.  Somebody correct me if I’m wrong.

You’re probably correct for the actual bare minimum. The number I always use is 35 as my personal bare minimum - it’s a little more forgiving.

That is pretty low, might require decoctions to help it along.  8)

Devil!  ;)  So, what would you consider the lowest?

People love to talk about enzymes and diastatic power and all that jazz, but in layman’s terms, what you really want to look for is:

  1. It’s malted.

  2. It’s light in color.

  3. It’s not caramel or crystal or biscuit or honey malt – these are exceptions to the rules.

That’s about it.  Keep those things in mind and you’re golden (no puns intended).

35 is often stated to be as low as you want to self convert.

Thats what I heard. And at that a lot of people toss in pils or 6 row to boost

That’s so 20th century… loooooong time ago.  :wink: