Using Flaked Oats, Wheat, etc.

I just brewed a light ale to add raspberries with later in the secondary. For 5 gallons extract, I boiled 1 lb of light DME for 50 minutes then added 3 more lbs of light DME, 1 lb of dry rice solid, and 1 lb of flaked oats for the last 10 minutes. I was hoping the extra rice solid would get the gravity up to about 1.05. However, the oats seemed to have soaked up much of the wort and I only got an OG of 1.036. Can anyone tell me if this is to be expected or did I do anything wrong...bad recipe? Thanks.

Flaked grains have to be mashed with base malt. Then you boil what runs off them rather than boiling them directly.

And I think that whole cereal grains like rice require a "cereal mash" step before that to render them physically ready. Flaked grains undergo that transformation during the flaking.

If I am off-base, someone pls correct.

Fratermus is correct.

Steeping or boiling unmalted oats wheat or rye will not contribute anything positive to your brew. They lack enzymes to convert themselves. They need to be mashed with at least a small amount of malted barley. Boiling in fact will only result in adding starches and proteins to your beer making it hazy and less stable in terms of aging.