>>Kefir has more acid than many acidic beverages and has a wider range of acids.

Aha! Thanks for that clarification - didn't occur to me. Wanted to learn more, discovered article below. Revealing, to say the least (not limited to its acids analysis):

http://ift.confex.com/ift/2000/techprogram/paper_4630.htm


Amino Acid Profile of Kefir

(1) Justification: Kefir is a fermented dairy product prepared by inoculating whole milk with kefir grains. The complex mixed culture of the kefir grains produces the carbonated product that contains a unique mixture of lactic acid, ethanol, acetaldehyde and acetoin. (2) Objectives: The objective of this study was to determine the amino acid profile of kefir as compared to yogurt and milk. (3) Methods: Kefir was prepared by inoculating heat treated whole milk with kefir grains and incubating at 28°C for 24 h until the pH reached 4.5-4.6. Yogurt was prepared by inoculating heat treated whole milk with Chr. Hansen YC 180 culture and incubating at 42°C for 3 h until the pH reached 4.6. A sample of whole milk was retained as a control. Kefir, yogurt and milk samples were freeze dried. Samples were pretreated by acid hydrolyzation for determining the total amino acid profile. Samples were pretreated by performic acid oxidation for methionine and cysteine determinations and by basic hydrolysis for tryptophan determinations. Ion exchange chromatography was used to resolve samples for amino acid profile. (4) Results: Threonine, serine, cysteine and lysine were in higher concentration in kefir samples than ino milk and yogurt samples. Ammonia was in lower concentration in kefir than in yogurt and milk samples. The concentration of methionine was highest in milk followed by kefir and then yogurt. Kefir and yogurt samples had higher levels of tryptophan than milk samples. (5) Significance: Results indicate that kefir has a unique amino acid profile different from milk or yogurt.