Originally Posted by twofortythree
This is my first batch of mead. I put it in my carboy 72 hours ago. I noticed that the fermentation lock was not bubbling consistently, but the yeast was producing a lot of gas bubbles. I put some electrical tape around the cap and the fermentation lock started bubbling every 1-2 seconds. My question is how likely is it that my batch is contaminated/ruined? I used 9 lbs. of honey and 3 gallons of distilled water, yeast for a 4 gallon batch and yeast nutrients. Thoughts?
Little to no chance.
When you seal the fermenter, there's just the air inside, which could, theoretically, have had some contaminants.
Yet as soon as some of the yeast cells start doing their thing, they start to produce CO2.
CO2 is a "heavier than air" gas, so the surface is quickly blanketed by a layer of it, and any air will be expelled through whatever exit it can find i.e. if it was all completely blocked off, you'd have seen a bucket lid starting to stretch until the pressure is great enough to pop part or all of the seal for the pressure to escape, similar with a bung in a carboy/demi-john type fermenter, except as they tend to be glass, you don't see any movement, you just know about it if/when the bung pops out.
So it's rather unlikely that there will be a problem as the ferment is creating a layer of CO2 and keeping the pressure inside the fermenter at a slightly positive pressure level.
If you can see through the container, you watch out for stuff like (seemingly) white spots, often with trailing snotites hanging from the white spots/patches etc, or also vinegar type acidic smells (don't forget, it depends on the ingredients but you can get some very "funky" smells from a live ferment - it's usually "negative" smells that are a problem).