Baby suddenly not keen on lumps.

Ra
My son is 8 & 1/2 months. I make purées and also do a bit of BLW. He was on mashed texture purées with some lumps but suddenly he won't take purées with lumps they have to be completely blended. If he find a lump he then stops eating and won't open his mouth of blows raspberries. He won't eat jarred food (I would only give when out and about) he only eats homemade food. How can he be this picky so young? 
He will chew on rice cakes, bit of fruit and veg etc but just won't take purées or porridge etc with lumps in. He's nearly 9 months so I know I can't keep giving him blended purées or it might cause more problems.