I'm currently fermenting two batches of mead, which are in the primary with blowoff tubes. I was away from the house for a month. I did not anticipate the evaporation of water from the jars acting as my airlock, and came home to find the tubes hanging in air (the tips were no longer submerged).
I know that CO2 is heavier than O2, but I'm concerned that due to air circulation, oxygen may have entered the tubes and displaced CO2 from the headspace in my demijohns. I will rack and top-up the mead ASAP as a precaution, just wondering what the likelihood of this having occured is...
Thanks for the input,