« on: March 18, 2013, 07:54:38 PM »
I used the sour worting procedure once, successfully thank goodness. I had read that the malt-based lacto introduction sometimes results in a big specific gravity drop that you are experiencing by souring your mash/sparge runoff, I believe based on creating an aerobic reproduction cycle vs. anaerobic reproduction. I'm sorry I don't recall the specifics. It was enough of a risk, and purportedly avoidable by inoculating the starter with a commercial lacto strain (Wyeast), that decided me to use the commercial strain. The problem is that any alcohol created by the lacto starter souring process (if that indeed occurs) is lost when you boil the wort with hop additions. So, the starting gravity of your beer will be the final gravity after the starter is done souring the runoff, although it will increase just slightly due to evaporation during the boil. You will end up with a low ABV beer after the beer yeast fermentation.
When I added my sour starter my runoff was at 1.053. When soured after 67 hours, the SG was 1.050, but part of the drop I attributed to adding the 1/2 gallon 1.033 lacto starter. For my situation I added 10 oz. of DME, and ended up with an OG of 1.057 for 11 gallons after a 90 minute boil.
Sounds like you have a good degree of sour in your wort so go ahead and boil with hop additions when you're ready, and I would calculate how much DME or LME you need to add to bring your wort up to a proper starting gravity prior to inoculating with brewer's yeast.