I just thought I should say this, I have never heard of 'bia'. In Swahili beer is Pombe not bia'.
I hope it helps
Apparently that's a Kenyan thing. In Tanzania, as far as I've seen, pombe generally refers to home-made alcohol and bia is used for beer.
Actually I am a kenyan.pombe is beer. bia ni utohozi kutoka kwa jina beer in English.its used mostly at the coast.For local beers they have local names.