Vanilla Beans and Wild Yeast

I've been brewing for a few years now and in that time have made two beers with vanilla beans added to primary after fermentation has ended (using hydrometer readings). In both batches, I sanitized the beans by soaking in 40% abv hard liquor, and both of my beers have turned out over-carbonated. I don't attribute this to time in bottles for co2 absorption because they both had at least 3 weeks in bottle at 70 degrees. Is there any way wild yeast/bacteria survived the soaking in alcohol?

I am about to add vanilla that has been soaking in Jack Daniels and oak cubes to an old ale. I am curious about the sanitation from the hard liquor myself. Hope someone has had experience with this.

Haven't had personal experience myself, but a mate of mine has made a chocolate stout a few times that calls for vanilla beans. He uses a decent, but not too expensive vodka around 40% abv. He soaks the pods for at least a week in the vodka and adds it along with the vodka used to soak the pods to primary 3 weeks after pitching yeast. No infection or over carbonation. perhaps you did not soak the vanilla long enough or had some sugar priming issues? Maybe you could somehow boil the vanilla for 5 minutes in water, drain, and then soak in vodka or rum?

I routinely throw vanilla beans directly into the fermenter with no prep other than slicing them open. I doubt your carbonation issues are anything to do with the vanilla beans.

I dump 8 ounces of drunken cocoa nibs into my chocolate stouts without any untoward issues. It sure seems unlikely that a thoroughly soused bean or two could be the cause of an infection...

Cheers!

One of the batches of beans soaked in bourbon for a week. The other in vodka for about an hour. Does anyone think the tiny beans that might've made their way to the bottle are providing nucleation points? I don't cold crash or filter.

I think you need to soak at least a week. Maybe the small beans do pass