Certainly not too late, toss it in. Your beer probably will never get as sour as a commercial lambic, but you should be able to get some tartness with extended age. Donít worry if it starts to taste a bit buttery, the Brett will clean it up over time. You could also just toss in the dregs from a few bottles of sour beer, often the "wild" strains are more agressive than the Wyeast and WHite Labs cultures.
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