I have been brewing in my basement for about 3 years now, maybe four. Before that I brewed on my enclosed back porch. I always have fermented in my basement and have had this issue for years. The first batch i remember this happening with was a Sour Raspberry i brewed in 2015. I did not use lacto on this. I just soured it by using Lactic Acid and the tartness of the raspberries. I did brew a Berliner about a year before that and used Lacto Brevis. But I still have some bottled beer brewed between those two that does not gush.
When the beer does gush, i would say there is an off taste. I would not describe it as sour or funky. May be closer to a grape juice flavor.
A Wee Heavy i brewed in March was in the fermenter for a month to be sure it was done. I bottled in April and purposefully undercarbed. After about 4 weeks, the first bottle I opened gushed. This was with White Labs Edinburgh ale yeast. I degassed a sample and it is nearly 13 gravity points lower than when i bottled. Which makes me think it has to be between the fermenter and the bottle.
Sediment at the bottom of the bottle isnt that bad really, but I honestly can't say i really every looked at it closely to see how much there was.
I have used Saison yeast a few times over the years, Belle Saison being one of them. I read somewhere this has diastatic yeast in it. I have not used Brett for close to 15 years.
I use 3 piece ball valves and always dissemble after every brew day. The only thing I don't take all the way apart every time are my quick disconnects and some other stainless fittings.
As for sanitizers...I have used One Step, StarSan, and Iodaphor.
I did replace my bottle bucket a year or so ago, and I have replaced my tubing and siphon...but not at the same time.
Assuming it is ok through the boil, then I would need to replace my all my fermenters (or ferment in glass), siphon, tubing, plastic spoons, bottling bucket, wand...anything else????
