On Food and Cooking

restarts its biochemical machinery and
produces various enzymes, including some
that break down the barley cell walls, and
others that break down the starch and proteins
inside the cells of the food-storage tissue, the
endosperm. These enzymes then diffuse from
the embryo into the endosperm, where they
work together to dissolve away the cell walls,
penetrate the cells, and digest some of the
starch granules and protein bodies inside. The
embryo also secretes the hormone gibberellin,
which stimulates the aleurone cells to produce
digestive enzymes as well.
The maltster’s aim is to maximize the
breakdown of the endosperm cell walls and
the grain’s production of starch-and protein-
digesting enzymes. The cell walls have been
adequately weakened by the time that the
growing tip of the embryo reaches the end of
the kernel, some five to nine days after the
grain is first soaked. If the maltster is going to
make a pale malt, then he keeps starch