Very sour beer for blending?

[marqoid]

I have several carboys of wild beer, but none are quite sour enough. I want to experiment with blending them and adding a more sour beer to increase acidity. I don't want to use straight lactic acid.
What is the best way to make an extra sour base beer for blending/balancing?
Low gravity low hopped beer and just pitch lacto?
Low gravity low hopped beer and just pitch pedio and add brett after a few months?
Lots of acid malt?

 

[ardyexfor]

I cultured up some lacto from grain and stepped it up to a gallon+. Pitched this into a 5 gallon berliner weisse and let go for two days before pitching brett. Let it go for a couple months more and its sour as all hell and very clean, almost nothing from the brett.