On the top of my carboy (5 gallons) I had a small cap that I put a hole through and then reinforced the sides of it with glue (Duco Cement, http://www.devcon.com/products/products.cfm?familyID=207
, similar to plastic model glue). My plan was to stick the rubber tubing through to serve as the blow-off tube (the other end in a small bucket of sanitized water). Upon racking, when one end of the tubing was put in the fermenter as the end of the siphon, the cap fell in! The glue had been dry for a few days but must not have had a strong enough bond.
I didn't notice the cap in the wort at the time nor did it come to mind until after everything was sealed and I had left the house. Unfortunately, I am now on vacation and will not return for a few weeks.
The question is, how much will taste or other things about the beer be affected with the cap and some hardened plastic glue residue in the wort during primary fermentation? I am brewing an Oktoberfest lager and there will be a diacetyl rest and secondary fermentation. Should I fish out the cap upon my return and continue or just start anew? Of course I will have a proper carboy plug and keep all chemicals away from the beer in the future.