How can I increase bifido bacterium strain density in kefir Both water and milk kefir contain Bifido strains and I would like a way to increase the density of bifido strains.

If the variety of strains could also be increased, that would be a bonus.

Bifido is anaerobic and consumes oligosaccharides (I think), so could adding juiced chickpeas after initial fermentation has removed all the oxygen work?
The simplest way to increase the diversity of strains might be to start from a mixture of kefirs from the most diverse and independent sources you can find. There's no guarantee that putting two symbiotic communities together will improve either of them though, or produce a final more diverse community.

What are the constraints on density? I would imagine that density will increase until either nutrients are depleted, or pH or other toxicity factors reach a certain limit. You might find that some strains tolerate a higher/lower pH range than others, and also that careful pH adjustment would allow density to keep increasing, provided you supply enough nutrient.