Never tried growing my own kefir, but our local Polish shop sells it, I go through about a bottle a week, about 70ml a day. I do tend to mix my kefir with a spoonful of raspberry jam to make it sweeter, which is probably cheating and defeating the purpose. Might try mixing kefir with banana, I hear they like banana with all its tasty oligosaccharides.
The big difference between it and probiotic yoghurt is range of microorganisms in kefir. Commercial yoghurts advertise billions of 1 variety of bug, while kefir is whole ecosystem, not just bacteria, friendly yeasts too.
Probiotic activity of mixed cultures of kefir's lactobacilli and non-lactose fermenting yeastsKefir is a product manufactured by starter culture prepared from kefir grains. The grains were kept in leather bags or horseback, only added milk. In the warm climate fermentation began. Kefir grains are very complex, and as they vary from region to region, from dairy to dairy, no thorough and unambiguous identification of its components are possible. However studies show that all kefir grains consist of lactic acid bacteria and lactose fermenting and non-lactose fermenting yeasts, growing in a strong relationship (Farnworth,2005).
1. Bacteria found in kefir grains and kefir:Lactobacillus kefir
Lactobacillus delbrueckii
Lactobacillus kefiranofaciens
Lactobacillus rhamnosus
Lactobacillus kefirgranum
Lactobacillus casei
Lactobacillus parakefir
Lactobacilli paracasei
Lactobacillus brevis
Lactobacillus fructivorans
Lactobacillus plantarum
Lactobacillus hilgardii
Lactobacillus helveticus
Lactobacillus fermentum
Lactobacillus acidophilus
Lactobacillus viridescens
Lactococcus lactis subsp. lactis
Lactococcus lactis subsp. cremoris
Streptococcus thermophilus
Enterococcus durans
Leuconostoc sp
Leuconostoc mesenteroides
Acetobacter sp
Acetobacter pasteurianus
Acetobacter aceti
Bacillus sp. r Micrococcus sp. r
Bacillus subtilis g Escherichia coli r
2. Yeasts found in kefir grains and kefir:Kluyveromyces marxianus
Saccharomyces sp.
Saccharomyces cerevisiae
Saccharomycesunisporus
Saccharomyces exiguus
Saccharomyces turicensis
Saccharomyces delbrueckii
Saccharomyces dairensis
Torulaspora delbrueckii
Brettanomyces anomalus
Issatchenkia occidentalis
Candida friedrichii
Candida pseudotropicalis
Candida tenuis
Candida inconspicua
Candida maris
Candida lambica
Candida tannotelerans
Candida valida
Candida kefyr
Candida holmii
Pichia fermentans
The Mary Jones article mentions bacteria in your intestine that produce endotoxins. You get the same thing with meningitis bacteria in your blood stream, when the bacteria die, killed by antibiotics or your immune system, they release the endotoxins which cause the damage. Start off with too much kefir and your new friends will start massacring all the nasties living in your intestine releasing their endotoxins, which you system will want to get rid of fairly rapidly. You want a gentle colonisation, where your unwelcome residents are slowly squeezed out. Ease yourself onto it. And if it upsets you system, cut back the amount you are taking for a while.