Making Malt-Free Bread
Added malt is not necessary for yeast action.

The starches in flour are huge sugar molecules. They are too big for our tongue which is why we can't taste them. They are also too big for yeast to break down.

Given some time amylase enzymes in the flour will break some of those starches down into natural malt. This gives dough more complex flavors as well as a considerable amount of sugar for us and for our belching yeasty slaves. For this reason it is added to some flours by millers. Peter Reinhardt has made a career talking about this.

However, this malt, while delicious, is not always necessary. The flour milling process produces plenty of damaged starches that the yeast will happily munch on. For many breads this is entirely sufficient for proofing.

If your flour does not have much amylase and no added malt (which can also add enzymes) then your dough won't be breaking down any of your starches into new sugar. If you age your dough for a long time your yeast could simply be starving to death. You monster.

If you consider your constant quest for convenience to be corrupting the quality of your carbohydrate-consuming companions and curtailing the quantity of carbon-dioxide- an easy way to test this theory would be to mix in a little sucrose (table sugar). Your indentured yeast will love you and will honor your reign with gassy uprisings.