Pre-boil PH in a Kettle Soured beer.

According to this site, a PH of 3.3 will be strongly tart, and anything lower than 3.5 will start to stress some strains of yeast. I would think that 3.6-3.8 would probably sound about right. You could taste it to see how tart it is, though I've found with kettle-souring that the pre-fermentation sugars tend to smooth out the tartness, making it a little difficult to gauge how tart the final product will be.

 

Agree with these points, but here is one way to deal with it: do a 100% brett fermentation after kettle souring. Brett has no problem with those pH levels and works well in hoppy beers.

 

There's that option as well. I've never done a 100% Brett beer myself. Does primary fermentation take longer than if using a Sacc strain?

 

Confession time: I've never done a 100% brett fermentation. But my understanding is that it functions much like a sacc fermentation, except that you should use a higher starting cell count (more like a lager). The brett does not (I am told) continue fermenting beyond the FG that it reaches fairly quickly, so no, fermentation doesn't really take longer, in stark contrast to the situation where you add brett to a fermentation along with sacc yeast. But bear in mind this is all just what I've read.

I do hope to try it soon. Because brett is tolerant of low pHs, it seems as though it would work great with lacto for a fairly quick and flavorful sour. I just haven't gotten around to it.

 

This intrigues me. I've had many commercial Brett beers, but have been too intimidated to brew one myself because I was under the impression that aging was required to ensure fermentation was finished and to avoid bottle bombs. If that's only true of secondary or mixed fermentations, I may have to start planning some of these for the summer.

 

Yeah, check it out. It looks as though primary fermentation is a little slower than sacc, but not much.

[Edited to add: Read the whole page, though, it seems as though there is some uncertainty about these issues.]

Also if you haven't bought American Sour Beers, it seems as though it might be a good purchase for you.

 

Yeah, so, brett is out I guess. For your purposes, I think a pH of 3.8 would basically be fine for most yeasts? I don't really know. This blog post and the related BYO article may be of assistance to you.

[Edited to add: I think 3.6-3.8, as you originally proposed, would put relatively little strain on most sacc yeasts. I didn't mean to imply that you needed to be at the upper end of that range. But remember, this is guesswork on my part, I hope the link helps you.]