Yikes! What's going on with my mead?!

[worlddivides]

So I racked my orange blossom mead to tertiary a couple days ago and added 1 ounce of French oak cubes. Fermentation on my mead finished after 2 weeks (at a final gravity of 0.995) and there has been zero activity for almost 3 months. But about 12 hours after I added the oak cubes, I noticed that the volume in my carboy was about an inch lower than it should have been and there was a bunch of foam on the top. I pushed the side of the rubber bung to let some air in or out and heard a HUGE hissing sound and the mead quickly went back up a full inch. I thought this was odd, but left it as-is. The next day I noticed that the mead was again lower than it should have been, but by about half an inch instead of a full inch. I pushed the rubber bung to the side again and heard a hissing sound, but not as loud of a one, and the mead level went back to normal.

What's going on here? How could the oak cubes be producing CO2?

 

[loveofrose]

Are you stopping it completely with a rubber bung or do you have it under an airlock?

 

[ChefRex]

Did you sanitize the oak in anyway? If not you could have introduced something wild.

 

[worlddivides]

Are you stopping it completely with a rubber bung or do you have it under an airlock?

Stopping it completely with a rubber bung. I stopped using the airlock about 2 and a half months ago.

Did you sanitize the oak in anyway? If not you could have introduced something wild.

I did not sanitize the oak, but it was delivered in an air-sealed container, so as far as I know, there shouldn't have been any need to sanitize it. From everything I've read and been told, anything in an air-sealed container (such as corks) should be sanitary before the container is opened.

 

[ChefRex]

I would put an airlock back on it and keep an eye on it.
A sour mead is on my radar, time will tell

 

[worlddivides]

I would put an airlock back on it and keep an eye on it.
A sour mead is on my radar, time will tell

Although I absolute adore sour beers, I'm not sure how I feel about a sour mead.

I'll leave it as-is for the moment and check it tomorrow to see if the mead level is different like it was yesterday or today and if there's any CO2 hiss, and if there is, I'll put the airlock back in.

I'm hoping that there was just some CO2 still in the mead that the oak has been (somehow) pushing out. :cross:

One possibility, I guess, is that when I racked to tertiary, I topped it up with some white wine (sauvignon blanc) to avoid exposure to oxygen. I specifically picked a dry white wine so that there wouldn't be any residual sugar that the yeast would eat into, but I guess it's possible that the small amount of wine I added (maybe 300-400ml) might have given the yeast something to eat.

 

[ChefRex]

Although I absolute adore sour beers, I'm not sure how I feel about a sour mead.

I'll leave it as-is for the moment and check it tomorrow to see if the mead level is different like it was yesterday or today and if there's any CO2 hiss, and if there is, I'll put the airlock back in.

I'm hoping that there was just some CO2 still in the mead that the oak has been (somehow) pushing out. :cross:

Look around, someone wrote an article about sour meads on this forum, enticed me.

 

[loveofrose]

Long after fermentation is complete, there is residual CO2 trapped in the mead. Adding oak provide numerous nucleation points for the CO2 to go back to gas which leads to pressure build up. This is one of the reasons that oak can actually help speed alone clearing. (Because nucleated CO2 isn't rising yeast particles back to the top).

Keep an airlock on at all times. Otherwise, you risk the bung blowing off and oxidizing your hard earned mead!

 

[worlddivides]

Long after fermentation is complete, there is residual CO2 trapped in the mead. Adding oak provide numerous nucleation points for the CO2 to go back to gas which leads to pressure build up. This is one of the reasons that oak can actually help speed alone clearing. (Because nucleated CO2 isn't rising yeast particles back to the top).

Keep an airlock on at all times. Otherwise, you risk the bung blowing off and oxidizing your hard earned mead!

I've never used a bung on beer or cider, but I got one specifically for mead just because I'm bulk aging it for so long. I thought a bung would be good to use on any wine (including mead) that would be aged in carboys for such a long time and I had read that I should use a bung once the fermentation had 100% completely stopped (which it had).

Also, thanks so much for the info. I think you're definitely right about the nucleation points, especially since it's seemed to go down more and more each time I've checked. If it was actually fermentation, I would expect the opposite. More and more CO2, not less and less.

EDIT: I checked the level right before going to bed and it was about 1/4th of an inch lower than it should have been, so I ended up putting an airlock on there just to be safe.

 

[worlddivides]

Look around, someone wrote an article about sour meads on this forum, enticed me.

I would definitely buy a bottle of sour mead, but I don't think I'd want to try making one before trying it out (especially since it would probably take a year or more to make).