ph and yeast.

I brewed a berliner weiss that I did a sour mash on with a kombucha scoby, it was very sour and acidic when I boiled it with some hops and pitched a pack of safeale 05 at 68 degrees. Its been 48 hours and there's no activity. Its at 68 degrees now and I pitched plenty yeast for a 1.032 wort. I'm wondering if the low ph ( I don't have strips I'm determining this by the very acidic taste of it) killed my yeast.
My question is How low of a ph will kill yeast or cease fermentation?

Did you make a starter? When I make a sour mash beer I will make a small 1l starter and pitch that during high krausen so the yeast is awake and working when they hit that low ph. I find that there is enough momentum to carry the ferment even at higher ogs (1050 is where I like my super-berliner) and very sour.

The yeast wont even get started in a hash environment but if they are already busting ass and then you add them to the rough environment then they have a chance.

With out knowing the ph id assume in your case it wasn't enough to kill them but it was too low to have them wake up, rehydrate and get to work. They are in a very weak stat following storage.

I didn't make a starter because I'm using dry yeast. Ill give it a couple more days and see if anything happens. If not ill take your advice and pitch at high krausen. Thanks for the advice