Agree! The flavor profile is even more interesting when you use the 'handful of grain' method of innoculating a starter to produce a sour. Then you are getting a wide variety of organisms that are finally dominated by lactobacillus. Just remember that this starter must be propagated under anaerobic (oxygen-free) conditions or there is a good possibility that your starter will grow 'funky' organisms that you may not prefer in your beer.
I find that using the lacto starters from either Wyeast or White can be somewhat one-dimensional, so the handful of grain method is my preference.
By the way, if you create this starter, you can verify that you have produced a predominantly lactic culture by smelling and tasting the starter. It should be pleasantly tart and smooth. Be aware that the culture can go through some nasty smelling periods, but let it go and eventually the lactic bacteria will win and the starter should turn tart and smooth. Keep the air-lock on the starter until you can smell the right aroma. PS: you also have to perform your mash or wort souring in an anaerobic condition or you will get too much funky, non-lactic character in the beer.
+1 but I make it even more simple, without a lacto starter culture. I simply pitch the pack into the wort which has been boiled for 15 minutes and then cooled to 90oF. I hole the wort at 90 for 5 days and it sours to 3.8-4.0 pH, then follow with a traditional boil and hops, etc.
Yes, it produces some funky smells and raises eyebrows from my kids! The beer is pleasantly tart and very refreshing!
Martin, I might try the handful of grain method on the next batch and compare, sounds interesting indeed:)