Last January, I brewed a Lambic style ale with the following recipe (5 gallons/OG = 1.046): 3lbs Pils DME 3lbs Wheat DME 4oz Maltodextrin .5oz Hallertau at 60 min And I pitched the Wyeast Lambic Blend as well as some dregs from Drie Fonteinen Oude Geuze and Oude Gueuze Tilquin. As of last July, the SG was only down to 1.013 and as of today, it's 1.012, which seems a little light on attenuation. Additionally, it's mostly acidic and very light on funk. Considering both the reasonably high SG and the lack of funk, is there any downside to pitching a vial of Brett? I'm in no rush with the batch, but it seems like whatever mix of yeast and bacteria is in there has more or less pooped out. Should I also pitch some more bacteria (either dregs or a commercial blend), or is Brett my best option at this point to both lower the SG and balance the acidity?
Disclaimer: this is all theoretical as I have yet to brew a beer with bacteria. I don't think adding any bacteria will do anything for you. The funk they give is more of the soupcon of poop than the earthy wet hay and horse of brett. Adding a vial of brett may help you get the attenuation down and give you a boost of funk, but I would personally add a small starter of 3711 at high krausen and speed up the process. The brett will continue to devolop as it ages. This is just my opinion, I could very well be wrong and would like to know why in a constructive manner.
As MrOH suggested, Brett is what you need at this stage. It tends to go to hit its stride after the bacteria, and finishes off attenuation. A vial of the Brett of your choice would be fine. You could pitch some 3711, but with the acidity and alcohol this is already a tough situation for any brewer's yeast.
Although it might be an issue of alcohol tolerance instead of pH tolerance, Weyerbacher's 2010 Riserva comes to mind. They claimed low carbonation was due to the effects of the beer's acidity on the yeast. Would it be possible for the bacteria to overtake the yeast at work and acidify it to the point of inhibiting fermentation in this case?
I googled "sour beer pH" out of curiosity and your website was the first hit! Good read, haven't read that post before (I tend to jump around).
Embrace the Funk has a nice listing of commercial sour beer pH as well: http://embracethefunk.com/ph-readings-of-commercial-beers/
