Hi Maya,
First try the online health magazine - ‘la chispa’ - they mainly cover costa del sol, but do have advertisers further afield.
They are very friendly and I am sure if you dropped them a line they would have some suggestions of helath food stores in your area at least to get you started.
Our local store in Los boliches - Bionatura do buy in bulk - but I don’t think they would give us their supplier???
Is this the kind of item you can get at an agricultural store? I know our one in Alhaurin again have large sacks and if I asked nicely I am sure they would sell me a bag at a reasonable price. (They sell a whole range of grains and pulses. I am not sure if it is for caterers or for animals tho!). 😉
Happy eating;)
SJ