
No, milk doesn't have to be soured to make butter.
Skim the cream off it, whip the cream into whipped-cream, continue whipping it into very stiff whipped-cream, and then just DON'T STOP whipping it, and it'll soon start clotting into butter; no souring at all required.
I know this for a fact, 'coz we did exactly that as an experiment in Home Ec in the eighth grade. Thank GRR the electric whick was invented by then!
The liquid that remains, though, is a lot thinner than sour milk; just lightly white-coloured water, IIRC. (No guarantees I do, though; we didn't focus on that part AFAICR.)
[link|mailto:MyUserId@MyISP.CountryCode|Christian R. Conrad]
(I live in Finland, and my e-mail in-box is at the Saunalahti company.)
You know you're doing good work when you get flamed by an idiot. -- [link|http://www.theregister.co.uk/content/35/34218.html|Andrew Wittbrodt]