Airlock not working

[Muscadet]

I've had a batch going for three weeks but no bubbles from airlock. The mash only takes up about 2.5 gallons in a five gallon bucket. Should I put more yeast in it. When I open the bucket I smell fermentation. Thanks

 

[didinho]

if it smells fermentation, you have fermentation.
it's probably too low to move the airlock, with low production of gas.
don't open the bucket too much, to avoid infections

 

[Redlantern]

I also see that you said bucket. Reasonable chance the lid is leaking if you used a bucket.

 

[bernardsmith]

@Redlantern. There could be a leak between the lid and the bucket, and /or between the grommet and the airlock. The only reliable way to determine if fermentation is ongoing is to use your hydrometer. Correct sanitation protocols means that you can fill the testing cylinder, measure the gravity and return the sample back to the fermenter. Wine ain't beer.