Berliner Weisse won't sour

I made a Berliner Weisse in April and it still isn't sour. I'm starting to be discouraged. Here's the story so far:

Normal AG mash, short boil, quick cool.

Pitched S05 and the Wyeast Lacto blend simultaneously. The lacto had been in storage (fridge) for almost a year.

No souring after 3 weeks so I chalked it up to the Lacto culture being dead. I did a 10 gallon batch, so I decided to do an experiment.

One 5gal carboy got a White Labs Lacto culture that I bought and was dated as only 3 weeks old at pitching.

The other carboy got a "homemade" culture I made in a quart jar using some wort and a handful of pilsner malt. I let this sit for 3 days in my garage and then pitched the culture.

Both are still ticking the airlock (slowly) but now it has been 6 weeks since I repitched and still NOTHING.

Would it help to add some fermentables? The beer is currently at 1.003 and is stored at ~65f.

The only other thing I can think of is that the pH is too low, but I haven't checked it, nor do I have a way, although I can buy some litmus strips.

Time

In my experience, the commerical lacto mixes sour very slow. It could easily take 6 months to a year to develop the desired sour character. I have had excellent success with sour mashing to get the complexity and tartness in a berliner weisse.

Lactobacillus takes about 6 months to fully develop the sourness in the finished beer. If you want it quicker than that you can cheat and add lactic acid, about 1 oz will pucker up a 5 gal batch nicely. Or do the sour mash.

Low pH wouldn't be the issue if the beer isn't sour. I've found that my beers only take a couple months to get as sour as they are going to with Lacto. I've found that I need to get the Lacto going along with the primary yeast, as far as I'm aware it doesn't have the ability that Pedio/Brett do to breakdown really complex sugars.

Any idea how many IBUs the beer had, Lacto is very sensitive.

I'm guessing either low ph or not enough lacto.

For my last berliner I made a 2 vial lacto starter several weeks in advance to give it plenty of time to grow. I actually pitched the lacto starter first giving it a chance to take hold and it was in a full kerausan within 24 hrs (I did pitch a little warm). Once the lacto had taken hold, I pitched the sach yeast.

I sampled it after only 2-3 weeks in the bottle and it was certainly sour, with a little sourness continuing to develop in the bottles over time.

I have a Berliner that has been in the keg conditioning for a year and it still is not as sour as I want it to be, but its getting there.

one trick that worked for me in the past was to cool the wort to 100-105ºF then pitch the Lacto culture (if you can make a starter and expand the Lacto) Try and insulate your fermenter, or if you can keep it at 100º for 12-24 hr, then let it cool to 64, and pitch your chosen yeast.

Thanks for all the good advice. I still haven't checked the pH, but the IBU is 5 for this batch. I do thing the ale yeast got all the simple goodies and the lacto just does'nt have anything to eat. I am going to do some experimentation since I have two carboys for comparison.

I am going to rack them both again to get them off any dead yeast that has flocculated.

The carboy with the White Labs culture will get a dose of 4 oz priming sugar and a week of elevated temps in the fermentation "fridge". I'll dial in temps of about 85f and see where it goes.

The other carboy with the homemade lacto culture will go into the back corner of the cellar to be checked monthly.

Does anyone have any strong opinons against this? It may seem like I'm in a hurry to get results, but I'm a tinkerer and am curious how different methods affect quality of the finished beer.