There really is no such thing as "weak" fermentation, or "strong" fermentation, or "good" or "bad" there is only FERMENTATION. If you have fermentation, then it is all good.
We're dealing with living micro-organisms, and tons of affecting variables in each fermenter. Slight changes in temp from where sunlight might hit one fermenter differently over another by even a degree; proteins in solution, phases of the moon, yadda yadda yadda.....there's a lot going on.
There is nothing "typical" in brewing...No two fermentations are ever exactly the same. Even with the same recipe/yeast, etc. Too many variables at play in any given day.
When we are dealing with living creatures, there is a wild card factor in play..Just like with other animals, including humans...No two behave the same.
You can split a batch in half put them in 2 identical carboys, and pitch equal amounts of yeast from the same starter...and have them act completely differently...for some reason on a subatomic level...think about it...yeasties are small...1 degree difference in temp to us, could be a 50 degree difference to them...one fermenter can be a couple degrees warmer because it's closer to a vent all the way across the room and the yeasties take off...
Someone, Grinder I think posted a pic once of 2 carboys touching each other, and one one of the carboys the krausen had formed only on the side that touched the other carboy...probably reacting to the heat of the first fermentation....but it was like symbiotic or something...
Yeasts are like teenagers, swmbos, and humans in general, they have their own individual way of doing things. So it's never a good idea to compare one fermentation to another.
That's why I tell people not to read meaning into any so-called "signs of activity" other than gravity changes. Because they are for various reasons never usually a direct association with what the yeast is actually doing in the beer. They can just as easily be affected by environmental conditions as anything else.
All that matters is that the yeast is eating the sugars, (which 99.99999% of the time they are) not how the airlock bubble or doesn't bubble or even what the krausen does or doesn't do, or looks like for that matter.
Activity, action, bubbles, even krausen can be affected by the envoironment just as much as it being caused by the yeast...so going by that is NOT reliable.
If you want to know what's going on with your beer, then take a gravity reading. But really don't hover over you fermentors worrying about size or number of bubbles. It means nothing in the grand scheme of things.
You don't need to "do" anything, because nothing is wrong...except you are equating signs with too many variable to actually mean anything with a cause to worry.
