Vanilla Extract Project: Failure

So, I went to check on my vanilla extract project and found it to be a failure.

Oh yeah, they look fine from far, but look closer and you'd see this:

Um... what? Is that mold in 80 proof vodka??

(I made the image a little smaller so you don't have to see the detail in its gross glory.)

Just like that, $50 down the drain. I don't really know what went wrong here but I made this little image of some possibilities:

I'm still surprised that mold can grow at all in 80 proof vodka. I accidentally knocked one of the bottles over without any spillage so I don't think it's the airtight issue. Although, it looked like a lot of recipes I found online used mason jars. It doesn't really make much sense for it to grow mold just because it wasn't covered all the way, especially since only the submerged part grew. And the vodka? It's vodka.

I'm thinking it's the Rodelle beans. What do you guys think? I don't know what else to change for the next time I try this.

Potlucks Galore

I need a recipe book for potlucks. I'm slated for FOUR potlucks this month alone, five if you count Thanksgiving being so close to Dec. I can't keep making the same dishes.

Any recommendations? Do you usually make a big batch of things that can be scooped up (like salads) or things that can be picked up one by one (like shrimp)?