Let me share you where we can buy brown rice in Barcelona
El Corte Inglés
The “El Corte Inglés” in front of Catalunya station is very crowded. So, I will recommend other El Corte Inglés shops in other area to buy brown rice.
At the top of the photo, the rice “Bomba” packed by cloth is a rice from local Catalunya south area.
I was introduced the shop by local people. Healthy food shop. You can find it on some places.
I try to eat it at home. :)