- Barley: 60-65°C
- Wheat: 58-64°C
- Rye: 57-70°C
- Oats: 53-59°C
- Corn (Maize): 62-74°C
- Rice: 68-78°C
- Potato: 57-65°C
Starch gelatinisation is a process of breaking down the intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This irreversibly dissolves the starch granule in water.
You can bypass the cereal mash by using flaked or torrified grains as they've already had their starches exposed.
I stumbled across a few YouTube videos showing the starch granules physically breaking up during gelatinisation and releasing their contents. If a picture speaks a thousand words...
Potato lambic anyone? There's an idea.