How can I know the kind of acid produced by the bacteria?

[mloonjin]

I am busy identifying bacteria.and I know some bacteria would produce the acid when they were fermented.I want to know the acid belong to which kind.just like lactic acid ,butyric acid or else.what method I can use.
thank you in advance!wait for your good suggestion.

[mith]

butryic stinks, perhaps you could try some sort of spectroscopy, or maybe neutralize them and isolate the salts?