I use a Raspberry Pi with water-proof temperature probes to monitor the temperature of my fermenting wort, and I feed the probe through the airlock to make direct contact with the wort.
Two out of my last three batches have resulted in an overflowing airlock. For one of them I had to remove the airlock (and temperature probe) and replace it with a blow-off tube. This is undesirable for me as I then have to attach the probe to the side of the carboy with insulation material.
The other batch that I have right now is flooding the airlock but is not so bad that I have to replace the airlock with a blow-off tube. I am simply taking a paper towel and attempting to absorb some of the wort in the airlock, and then refill it with vodka up to the top.
My worry is that the wort in the airlock will become contaminated as it is a mixture of 40% vodka and wort, and that the wort next-in-line to enter the airlock will become contaminated and then the whole batch will become contaminated.
I could obviously just take the airlock out, wash it, and put it back in. However I had my first contaminated batch and have become adverse to taking the airlock out for short periods.
Can the wort inside an overflowing airlock contaminate the batch?