I've got two batches of my first mead fermenting and the bubbles seem to be slow but maybe this is normal. I have a 3 piece airlock and using I'm using Lalvin 1118 yeast in each gallon jug and they produce bubbles about every 20 seconds now which is down from last week when one was every 7 seconds and the other every 10 seconds. I'm not sure if this type of airlock produces less, though larger, bubbles than other airlocks I've seen? We did have a significant temperature drop when I was out of town for a few days (I think the temp in my house was in the low to mid 50's) and I realize this can slow the fermentation but wanted to get others thoughts and if I should do anything at this point?
There's little point in trying to diagnose the problem, if there is one, until you do as many checks as you can.
For instance, while it's bubbling etc, take some readings (usual to take 2 or 3 readings over a week) with a hydrometer. If the numbers are still dropping then the ferment hasn't stuck.
If you post your recipe and method, then those more knowledgable than me might be able to point you in the right direction for any potential problems.
Oh and if you can, check the pH. Yeast likes an acid environment but not too acid. If it drops below 3.0 pH you can get problems with stuck ferments.
If you know the gravity readings you'll be able to work out whether it needs more nutrient of some kind etc etc.
Bubble rate in the airlock is a poor guide of how the ferment is doing.
So in the first instance I'd suggest that you check the gravity and if it's not too far along, then aerate it (stir it), with the bung open. If you are worried that there might not be enough nutrient, but it's a bit far down the road, then just simmer a couple of teaspoons of bread yeast in some water (say 200mls) for 10 minutes, enough to reduce the water down, then let it cool and aerate before adding it.
regards
fatbloke