Sour Mash ideas

So, I brewed the basis for a sour fruit beer yesterday afternoon. I set aside 1g of wort and added 3oz cracked 2-row and added it. I made sure the temp was at 120 and wrapped it well with a sleeping back and placed it inside of a 5gal pot. It's been sitting outside (where its been in the 90s yesterday and today, even overnight).

So, I just opened the wort to see how it was progressing - not even the SLIGHTEST hint of sour. It's kept it's temp fairly well, so I don't have a clue as to why there is nothing going on. Ideas?

when the wild yeasts/lactobacilli find your wort, you'll know from the way it looks. the top will become unmistakably frothy. Sometimes it takes several days. If you cover it with some wire mesh or cheesecloth, that'll let airborn yeasts and bacteria in while keeping undesirables like flies and hair out. make sure it's in the shade.

you know what: nevermind. for some reason i thought you were intending to harvest wild yeasts...

its easier just to save part of the mash and let that sour. Then sparge it.