Anybody knows where to get sourdough powder on the island?

Guy, only sourdough powder I know is flour.

 

You can make your own sourdough starter with water and flour.  But it does take about 4 weeks until ready to bake.

Hi limbus, I buy my sourdough bread at BIG C in Pattaya Klang, it's exactly the way I like it and sliced if you require that, 80 baht for one which is about 13 slices. In saying that try the biggest BIG C in Phuket where many farangs shop, there's a fair chance that they will sell it too. Best of luck mate, it tried everything before I could buy it here in Pattaya. By the way it's the shape of half a decent sized water melon.

You could try Sampet in Nathon if you are passing. 

4 hours ago, Amusements said:

You could try Sampet in Nathon if you are passing. 

Just had a look in there, and did not see any (Unless it was in Thai).