Comment by Blackthorn

This must be different, the "old fashioned rolled oats" sold in America would be more than done after 20 minutes of simmering.

Going by Bob's Red Mill, which is an excellent brand, we've got: * Old Fashioned rolled oats, 10 minutes: https://www.bobsredmill.com/product/regular-rolled-oats [the store brand I always see, on the other hand, is 5 minutes]

* Steel cut oats, 15-20 minutes (this is a lie, it takes longer than 20 minutes for them to get sufficiently soft in my experience, for any steel cut oat brand): https://www.bobsredmill.com/product/steel-cut-oats

* Quick cooking rolled oats, 3 minutes (in my experience this is consistent across all store brands, down to 2 minutes): https://www.bobsredmill.com/product/organic-quick-cooking-ro...

They also have a second species of oats that are significantly higher in protein, and they take 15+ minutes to cook in "rolled oat" form, which from personal experience is accurate: https://www.bobsredmill.com/product/protein-oats